I just got infected from a web page with a virus that installed itself here
C:\Documents and Settings\USER\Local Settings\Application Data\sohham\sfsgsftav.exe
It poped up with a screen that looks alot like avast saying it had detected virus and would scan. Then it disable anything I tried to run, taskmanager, control panel, notepad. It would say their executable was infected and then shut them down. It also got to IE and prevented webpages from loading even though I could tracert route through cmd prompt.
I had to deny access to sohham directory through command line cacls. Restart in safe mode then manually delete it and remove the registry entries. I had to reset IE addins and settings to default then redo the settings I wanted.
Avast never caught it.