I know that viruses shouldn't be totally unexpected but I've been virus-free for ages as I run McAfee Security Suite, WinPatrol and Comodo BOClean.
In spite of all that something's managed to sneak through in the form of rogue pop-ups and messing with my desktop.
Every few seconds a WinPatrol warning pops up, currently asking approval for a new task: C:\Documents and Settings\All Users\Application Data\Guil1p78.exe with At42 written above. If I decline another one pops up immediately usually with another number next At.
I've run both SpyBot and Malwarebytes to combat it but nothing much has happened.
Any help gratefully received,