Okay, many people have actually had the same problem - only My Documents doing this. What they did was open RegEdit and browse to
HKLM/SOFTWARE/Microsoft/Windows NT/CurrentVersion/Winlogon and remove a duplicate of
userinit.exe. Since you got an Xfire folder coming up, I was thinking there could be something there that's making the Xfire folder start up.
You could alternatively just search the whole registry for
xfire and see if you come up with anything unusual.
HijackThis logfile?
Chris