Alright...today, I was around my PC, when I noticed auto-protect was disactivated, i tried to activate it, but it is useless, and I can't open Norton Anti-Virus too.

The most even problematic thing, is that taskmanager doesn't work(ctrl-alt-del). And regedit doesn't load too. This is a virus, I am sure. I thought it was Jeefo(I had to format C: the last time I had this one), that infects all exe files, but no...when i did a scan, it got no files infected...

I don't know what is going on, but this programs are important for my PC to work! Is there a solution?

UPDATE: New scan i did with Panda Antivirus freescan, noticed 3 files infected.
2 with Trj/Siboco.A
1 with Trj/Qhost.gen

They were both desinfected, says the antivirus.

http://securityresponse.symantec.com/avcenter/venc/data/trojan.qhosts.removal.tool.html
Above is the url for removing trojan qhosts.
http://www.pandasoftware.com/virus_info/encyclopedia/overview.aspx?lst=sol&idvirus=48204
The second url has the information on removal of Trojan Siboco.A