Assuming the tools you've used have not helped, you can edit the registry direct. Please note, if you've not done this before, don't do it until you understand what the registry does and what affects of getting the below (which is untested) wrong could mean!
Windows Instant Scanner manual remover:
Delete Windows Instant Scanner files:
Protector-[rnd].exe in %AppData% folder
Delete Windows Instant Scanner registry entries:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\
Inspector = %AppData%\Protector-[random].exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\a.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\aAvgApi.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\AAWTray.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\About.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\ackwin32.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\Ad-Aware.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\adaware.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\advxdwin.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\AdwarePrj.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\agent.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\agentsvr.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\agentw.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\alertsvc.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\alevir.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\alogserv.exe\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\AlphaAV\
Debugger = svchost.exe
HKEY_LOCAL_MACHINE\software\microsoft\Windows NT\CurrentVersion\Image File Execution Options\AlphaAV.exe\
Debugger = svchost.exe
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