My parents' Dell Inspiron tower goes to sleep within ~3 minutes of inactivity, despite every power setting in Windows (screen saver, turn off screen, go to sleep, turn off hard-disk, etc.) either turned off or set to 60 minutes.
This answer claims that Dell has been known to bundle their computers with software that can override these settings, but doesn't give any details (the problem for that user was being unaware of the advanced settings; I am aware of those). The only Dell software I can find running on the computer is Dell Backup & Recovery, which certainly doesn't seem a likely culprit.
Checking the Event Viewer for sleep events, I find that it is just an event by Kernel-Power saying "The system is entering sleep. Sleep Reason: System idle."
Full event report:
Log Name: System Source: Microsoft-Windows-Kernel-Power Date: 11/23/2017 3:59:02 PM Event ID: 42 Task Category: (64) Level: Information Keywords: (1024),(4) User: N/A Computer: WINDOWS-IN93UH3 Description: The system is entering sleep. Sleep Reason: System Idle Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-Kernel-Power" Guid="{331C3B3A-2005-44C2-AC5E-77220C37D6B4}" />
<EventID>42</EventID>
<Version>3</Version>
<Level>4</Level>
<Task>64</Task>
<Opcode>0</Opcode>
<Keywords>0x8000000000000404</Keywords>
<TimeCreated SystemTime="2017-11-23T20:59:02.222727900Z" />
<EventRecordID>11322</EventRecordID>
<Correlation />
<Execution ProcessID="4" ThreadID="11984" />
<Channel>System</Channel>
<Computer>WINDOWS-IN93UH3</Computer>
<Security />
</System>
<EventData>
<Data Name="TargetState">4</Data>
<Data Name="EffectiveState">5</Data>
<Data Name="Reason">7</Data>
<Data Name="Flags">0</Data>
<Data Name="TransitionsToOn">24</Data>
</EventData>
</Event>
The results of powercfg -l
Existing Power Schemes (* Active) ----------------------------------- Power Scheme GUID: 381b4222-f694-41f0-9685-ff5bb260df2e (Balanced) * Power Scheme GUID: 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c (High performance) Power Scheme GUID: a1841308-3541-4fab-bc81-f71556f20b4a (Power saver)
And powercfg -q
Power Scheme GUID: 381b4222-f694-41f0-9685-ff5bb260df2e (Balanced)
GUID Alias: SCHEME_BALANCED
Subgroup GUID: 0012ee47-9041-4b5d-9b77-535fba8b1442 (Hard disk)
GUID Alias: SUB_DISK
Power Setting GUID: 6738e2c4-e8a5-4a42-b16a-e040e769756e (Turn off hard disk after)
GUID Alias: DISKIDLE
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0xffffffff
Possible Settings increment: 0x00000001
Possible Settings units: Seconds
Current AC Power Setting Index: 0x00000e10
Current DC Power Setting Index: 0x00000258
Subgroup GUID: 02f815b5-a5cf-4c84-bf20-649d1f75d3d8 (Internet Explorer)
Power Setting GUID: 4c793e7d-a264-42e1-87d3-7a0d2f523ccd (JavaScript Timer Frequency)
Possible Setting Index: 000
Possible Setting Friendly Name: Maximum Power Savings
Possible Setting Index: 001
Possible Setting Friendly Name: Maximum Performance
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000000
Subgroup GUID: 0d7dbae2-4294-402a-ba8e-26777e8488cd (Desktop background settings)
Power Setting GUID: 309dce9b-bef4-4119-9921-a851fb12f0f4 (Slide show)
Possible Setting Index: 000
Possible Setting Friendly Name: Available
Possible Setting Index: 001
Possible Setting Friendly Name: Paused
Current AC Power Setting Index: 0x00000000
Current DC Power Setting Index: 0x00000001
Subgroup GUID: 19cbb8fa-5279-450e-9fac-8a3d5fedd0c1 (Wireless Adapter Settings)
Power Setting GUID: 12bbebe6-58d6-4636-95bb-3217ef867c1a (Power Saving Mode)
Possible Setting Index: 000
Possible Setting Friendly Name: Maximum Performance
Possible Setting Index: 001
Possible Setting Friendly Name: Low Power Saving
Possible Setting Index: 002
Possible Setting Friendly Name: Medium Power Saving
Possible Setting Index: 003
Possible Setting Friendly Name: Maximum Power Saving
Current AC Power Setting Index: 0x00000000
Current DC Power Setting Index: 0x00000002
Subgroup GUID: 238c9fa8-0aad-41ed-83f4-97be242c8f20 (Sleep)
GUID Alias: SUB_SLEEP
Power Setting GUID: 29f6c1db-86da-48c5-9fdb-f2b67b1f44da (Sleep after)
GUID Alias: STANDBYIDLE
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0xffffffff
Possible Settings increment: 0x00000001
Possible Settings units: Seconds
Current AC Power Setting Index: 0x00000e10
Current DC Power Setting Index: 0x00000384
Power Setting GUID: 94ac6d29-73ce-41a6-809f-6363ba21b47e (Allow hybrid sleep)
GUID Alias: HYBRIDSLEEP
Possible Setting Index: 000
Possible Setting Friendly Name: Off
Possible Setting Index: 001
Possible Setting Friendly Name: On
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000001
Power Setting GUID: 9d7815a6-7ee4-497e-8888-515a05f02364 (Hibernate after)
GUID Alias: HIBERNATEIDLE
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0xffffffff
Possible Settings increment: 0x00000001
Possible Settings units: Seconds
Current AC Power Setting Index: 0x00000000
Current DC Power Setting Index: 0x00000000
Power Setting GUID: bd3b718a-0680-4d9d-8ab2-e1d2b4ac806d (Allow wake timers)
GUID Alias: RTCWAKE
Possible Setting Index: 000
Possible Setting Friendly Name: Disable
Possible Setting Index: 001
Possible Setting Friendly Name: Enable
Possible Setting Index: 002
Possible Setting Friendly Name: Important Wake Timers Only
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000001
Subgroup GUID: 2a737441-1930-4402-8d77-b2bebba308a3 (USB settings)
Power Setting GUID: 48e6b7a6-50f5-4782-a5d4-53bb8f07e226 (USB selective suspend setting)
Possible Setting Index: 000
Possible Setting Friendly Name: Disabled
Possible Setting Index: 001
Possible Setting Friendly Name: Enabled
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000001
Subgroup GUID: 4f971e89-eebd-4455-a8de-9e59040e7347 (Power buttons and lid)
GUID Alias: SUB_BUTTONS
Power Setting GUID: 5ca83367-6e45-459f-a27b-476b1d01c936 (Lid close action)
GUID Alias: LIDACTION
Possible Setting Index: 000
Possible Setting Friendly Name: Do nothing
Possible Setting Index: 001
Possible Setting Friendly Name: Sleep
Possible Setting Index: 002
Possible Setting Friendly Name: Hibernate
Possible Setting Index: 003
Possible Setting Friendly Name: Shut down
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000001
Power Setting GUID: 7648efa3-dd9c-4e3e-b566-50f929386280 (Power button action)
GUID Alias: PBUTTONACTION
Possible Setting Index: 000
Possible Setting Friendly Name: Do nothing
Possible Setting Index: 001
Possible Setting Friendly Name: Sleep
Possible Setting Index: 002
Possible Setting Friendly Name: Hibernate
Possible Setting Index: 003
Possible Setting Friendly Name: Shut down
Possible Setting Index: 004
Possible Setting Friendly Name: Turn off the display
Current AC Power Setting Index: 0x00000003
Current DC Power Setting Index: 0x00000003
Power Setting GUID: 96996bc0-ad50-47ec-923b-6f41874dd9eb (Sleep button action)
GUID Alias: SBUTTONACTION
Possible Setting Index: 000
Possible Setting Friendly Name: Do nothing
Possible Setting Index: 001
Possible Setting Friendly Name: Sleep
Possible Setting Index: 002
Possible Setting Friendly Name: Hibernate
Possible Setting Index: 003
Possible Setting Friendly Name: Shut down
Possible Setting Index: 004
Possible Setting Friendly Name: Turn off the display
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000001
Power Setting GUID: a7066653-8d6c-40a8-910e-a1f54b84c7e5 (Start menu power button)
GUID Alias: UIBUTTON_ACTION
Possible Setting Index: 000
Possible Setting Friendly Name: Sleep
Possible Setting Index: 001
Possible Setting Friendly Name: Hibernate
Possible Setting Index: 002
Possible Setting Friendly Name: Shut down
Current AC Power Setting Index: 0x00000000
Current DC Power Setting Index: 0x00000000
Subgroup GUID: 501a4d13-42af-4429-9fd1-a8218c268e20 (PCI Express)
GUID Alias: SUB_PCIEXPRESS
Power Setting GUID: ee12f906-d277-404b-b6da-e5fa1a576df5 (Link State Power Management)
GUID Alias: ASPM
Possible Setting Index: 000
Possible Setting Friendly Name: Off
Possible Setting Index: 001
Possible Setting Friendly Name: Moderate power savings
Possible Setting Index: 002
Possible Setting Friendly Name: Maximum power savings
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000002
Subgroup GUID: 54533251-82be-4824-96c1-47b60b740d00 (Processor power management)
GUID Alias: SUB_PROCESSOR
Power Setting GUID: 75b0ae3f-bce0-45a7-8c89-c9611c25e100 (Maximum processor frequency)
GUID Alias: PROCFREQMAX
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0xffffffff
Possible Settings increment: 0x00000001
Possible Settings units: MHz
Current AC Power Setting Index: 0x00000000
Current DC Power Setting Index: 0x00000000
Power Setting GUID: 893dee8e-2bef-41e0-89c6-b55d0929964c (Minimum processor state)
GUID Alias: PROCTHROTTLEMIN
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0x00000064
Possible Settings increment: 0x00000001
Possible Settings units: %
Current AC Power Setting Index: 0x00000005
Current DC Power Setting Index: 0x00000005
Power Setting GUID: 94d3a615-a899-4ac5-ae2b-e4d8f634367f (System cooling policy)
GUID Alias: SYSCOOLPOL
Possible Setting Index: 000
Possible Setting Friendly Name: Passive
Possible Setting Index: 001
Possible Setting Friendly Name: Active
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000000
Power Setting GUID: bc5038f7-23e0-4960-96da-33abaf5935ec (Maximum processor state)
GUID Alias: PROCTHROTTLEMAX
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0x00000064
Possible Settings increment: 0x00000001
Possible Settings units: %
Current AC Power Setting Index: 0x00000064
Current DC Power Setting Index: 0x00000064
Subgroup GUID: 7516b95f-f776-4464-8c53-06167f40cc99 (Display)
GUID Alias: SUB_VIDEO
Power Setting GUID: 3c0bc021-c8a8-4e07-a973-6b14cbcb2b7e (Turn off display after)
GUID Alias: VIDEOIDLE
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0xffffffff
Possible Settings increment: 0x00000001
Possible Settings units: Seconds
Current AC Power Setting Index: 0x00000e10
Current DC Power Setting Index: 0x0000012c
Power Setting GUID: aded5e82-b909-4619-9949-f5d71dac0bcb (Display brightness)
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0x00000064
Possible Settings increment: 0x00000001
Possible Settings units: %
Current AC Power Setting Index: 0x00000064
Current DC Power Setting Index: 0x00000028
Power Setting GUID: f1fbfde2-a960-4165-9f88-50667911ce96 (Dimmed display brightness)
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0x00000064
Possible Settings increment: 0x00000001
Possible Settings units: %
Current AC Power Setting Index: 0x00000032
Current DC Power Setting Index: 0x00000032
Power Setting GUID: fbd9aa66-9553-4097-ba44-ed6e9d65eab8 (Enable adaptive brightness)
GUID Alias: ADAPTBRIGHT
Possible Setting Index: 000
Possible Setting Friendly Name: Off
Possible Setting Index: 001
Possible Setting Friendly Name: On
Current AC Power Setting Index: 0x00000000
Current DC Power Setting Index: 0x00000000
Subgroup GUID: 9596fb26-9850-41fd-ac3e-f7c3c00afd4b (Multimedia settings)
Power Setting GUID: 03680956-93bc-4294-bba6-4e0f09bb717f (When sharing media)
Possible Setting Index: 000
Possible Setting Friendly Name: Allow the computer to sleep
Possible Setting Index: 001
Possible Setting Friendly Name: Prevent idling to sleep
Possible Setting Index: 002
Possible Setting Friendly Name: Allow the computer to enter Away Mode
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000000
Power Setting GUID: 10778347-1370-4ee0-8bbd-33bdacaade49 (Video playback quality bias.)
Possible Setting Index: 000
Possible Setting Friendly Name: Video playback power-saving bias.
Possible Setting Index: 001
Possible Setting Friendly Name: Video playback performance bias.
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000000
Power Setting GUID: 34c7b99f-9a6d-4b3c-8dc7-b6693b78cef4 (When playing video)
Possible Setting Index: 000
Possible Setting Friendly Name: Optimize video quality
Possible Setting Index: 001
Possible Setting Friendly Name: Balanced
Possible Setting Index: 002
Possible Setting Friendly Name: Optimize power savings
Current AC Power Setting Index: 0x00000000
Current DC Power Setting Index: 0x00000001
Subgroup GUID: e73a048d-bf27-4f12-9731-8b2076e8891f (Battery)
GUID Alias: SUB_BATTERY
Power Setting GUID: 637ea02f-bbcb-4015-8e2c-a1c7b9c0b546 (Critical battery action)
GUID Alias: BATACTIONCRIT
Possible Setting Index: 000
Possible Setting Friendly Name: Do nothing
Possible Setting Index: 001
Possible Setting Friendly Name: Sleep
Possible Setting Index: 002
Possible Setting Friendly Name: Hibernate
Possible Setting Index: 003
Possible Setting Friendly Name: Shut down
Current AC Power Setting Index: 0x00000002
Current DC Power Setting Index: 0x00000002
Power Setting GUID: 8183ba9a-e910-48da-8769-14ae6dc1170a (Low battery level)
GUID Alias: BATLEVELLOW
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0x00000064
Possible Settings increment: 0x00000001
Possible Settings units: %
Current AC Power Setting Index: 0x0000000a
Current DC Power Setting Index: 0x0000000a
Power Setting GUID: 9a66d8d7-4ff7-4ef9-b5a2-5a326ca2a469 (Critical battery level)
GUID Alias: BATLEVELCRIT
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0x00000064
Possible Settings increment: 0x00000001
Possible Settings units: %
Current AC Power Setting Index: 0x00000005
Current DC Power Setting Index: 0x00000005
Power Setting GUID: bcded951-187b-4d05-bccc-f7e51960c258 (Low battery notification)
GUID Alias: BATFLAGSLOW
Possible Setting Index: 000
Possible Setting Friendly Name: Off
Possible Setting Index: 001
Possible Setting Friendly Name: On
Current AC Power Setting Index: 0x00000001
Current DC Power Setting Index: 0x00000001
Power Setting GUID: d8742dcb-3e6a-4b3c-b3fe-374623cdcf06 (Low battery action)
GUID Alias: BATACTIONLOW
Possible Setting Index: 000
Possible Setting Friendly Name: Do nothing
Possible Setting Index: 001
Possible Setting Friendly Name: Sleep
Possible Setting Index: 002
Possible Setting Friendly Name: Hibernate
Possible Setting Index: 003
Possible Setting Friendly Name: Shut down
Current AC Power Setting Index: 0x00000000
Current DC Power Setting Index: 0x00000000
Power Setting GUID: f3c5027d-cd16-4930-aa6b-90db844a8f00 (Reserve battery level)
Minimum Possible Setting: 0x00000000
Maximum Possible Setting: 0x00000064
Possible Settings increment: 0x00000001
Possible Settings units: %
Current AC Power Setting Index: 0x00000007
Current DC Power Setting Index: 0x00000007