When did this start?
There were a few new spyware/malware/viruses that prompted a few updates from Symantec, Adaware, Spybot, etc. just a few days ago. I know because a user at my work was foolish enough to click on a popup that said, "Hey, idiot, you might have spyware. Why don't you click on this link and allow me to take control for you and take care of that problem for you? Come on, do it." (not worded exactly, but you get the point).
When I initially ran scans, nothing was found. I didn't realize the updates were a couple weeks behind, did some research, did the updates. I ran the scans again and what was found was exactly what the definition updates were for. Trojan.KillAV(old, but recently updated), as well as a few other *.exe programs possibly resulting from the same virus(printer.exe found in c:\windows\ as well as something similar to winavex.exe, also found autorun.exe found in startup folder for 'All Users').
"Operation has been cancelled due to resirictions in place by the administrator" - or close to was the message given when trying to do anything. A repair install of the Windows OS didn't help either, it actually gave that error.
When I get into work Monday morning i will be nuking it. I was stubborn and wasted 4 hours on it Friday morning.