Devi rimuoverlo "a manina" ti scrivo qui sotto i passi da seguire che ho trovato sul sito di Mc afee, vale per un tipo di Opas, ve ne sono altre varianti;

All Users :
Use current engine and DAT files for detection. Delete any file which contains this detection.
Note: The virus alters the WIN.INI file on remote systems after it copies itself to that system. Therefore, VirusScan may detect and remove the virus before the WIN.INI change occurs. In the scenario users may see an error message that the file SCRSVR.EXE (or other file names) cannot be found when starting Windows. To fix this, follow these steps:

Click START - RUN
Type WIN.INI and hit ENTER
Locate the run= line and remove the necessary filename after the = sign
(ie. C:\WINDOWS\SYSTEM\SCRSVR.EXE)
Click FILE - EXIT and select YES when prompted to save your changes
Additional Windows ME/XP removal considerations

Se però tu hai Win Me o Xp devi prima disabilitare il System restore, altrimenti ricominci da capo, qui sotto hai il link con i passi da seguire:
http://download.nai.com/products/mca...SysRestore.htm
Spero tu risolva, ciao .