BEST.exe

There's some virus on my hard drive which interferes with Windows setting up.  There are new folders in my base driectory C:\FILES and C:\RECYCLER ( at  least these).  I also saw a SABER directory - don't know if it's related.  There is also this routine "BEST.exe" which shows during start-up.  I've run a scan using Norton and yet nothing is found.   Is there anything I can do?

Karen