I seem to be encountering a similar problem, but as far as I can tell, not from a virus.
The PC was running perfectly until I installed the latest Windows updates for XP, and now, no icons, taskbar etc. Although explorer.exe appears to be running in task manager, it isn't showing!! It will load eventually, but takes a good 10 minutes to do so.
I was wondering if anyone else had just updated before experiencing this problem?
It has to be said that it's only explorer that's playing up, I can access evrything else normally...task manager, reg edit etc.
I can also command a new explorer.exe to load from task manager, and everything will be fine till the next reboot.
Just a thought, but if any of you are experiencing this due to a Windows update, can anybody figure out WHICH update is responsible???