Sounds like that file is maybe REVOP.A from searching doesnt seem to be an important file as you havent commented on any other problems!
Try pandas online scan click here
SYSTEM RESTORE OFF!
Remember if you have XP you will have to turn off system restore before scanning as a virus can be hidden inside that too
If it doesnt detect a virus, then AVG would have removed it but not all the file refences so go START > RUN > MSCONFIG look thought that and find the SYSFLG32.EXE reference and delete it
IF NOT THEN REGEDIT..
If that doesnt work or you cant see the file goto C:\windows\ copy a file called REGEDIT (back up purposes) then open the orginal and search for the SYSFLG32.EXE and delete...