This is another place where you can read about viruses and also do an online virus-check: Panda

It sound like Bugberar which is known to affect antiviral programs.

Info from that site:
W32/Bugbear is a worm that reaches computers in an e-mail message which is very difficult to recognize, as its subject, contents and the name of the attached file are made up randomly.
W32/Bugbear affects several antivirus programs and firewalls in order to leave the computer defenseless against other viruses and attacks.
W32/Bugbear has a size of 50,688 bytes (compressed with UPX) and is written in the Visual C programming language. Additionally, W32/Bugbear drops a DLL file (dynamic link library), which contains a keylogging Trojan, detected by Panda as Trj/PSW.Bugbear 5632 (Bytes).

You can also find a tool there to remove it (when you've found what it is).

Good luck!

Berit