For some time, I've been getting random bleeping noises on my Windows 7 machine - the same noise as when the User Access Control prompt comes up (where it asks you for permission to do something). It happens even when I've closed all programs that have any sort of alerts or notifications to them. I've posted a screenshot below of all programs running, including those in the background in the taskbar. It actually bleeped right when I took this screenshot. It happens absence of any noticeable alert, change, notification, etc.
If anyone knows what might be causing it, that would be great, as it is quite annoying.
