Well I've just spend an evening removing the Klone virus from mine and my girlfriends PC - seems it came from the Kaaza installation program
So the steps I took...
first I looked in the system32 folder for any exe's that were dated with that days date... klone if a self replicating trojan so it makes files
I deleted them - any that wouldn't delete were running as a process so I stopped that process in Task Manager
I did the same in the windows folder.
I checked and deleted and suspicious entries in the "run" and "runonce" registry keys
Finally to stop the virus coming back I noticed a strange entry in the registry
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\shell
which should only have a value "explorer.exe" had another program attached - so I put the value back to "explorer.exe"
rebooted - ran avg - everything was repaired
Hope this helps