Help!!

:cry: I have been using AVAST on my PC for over a year; suddenly, I have a virus and I don’t know how to get rid of it; Avast cannot do it. It is located in C:\windows\system and is called mtwirl32.dll
The scan says it is a Trojan (gen). Can somebody help me??? PLEASE!!

Culpeper gives the solution here:
http://forum.avast.com/index.php?board=2;action=display;threadid=3286;start=msg23543#msg23543