Try doing a system restore, restore it to the earliest date you have on the list, or one where you think it may have been working.
Control panel=system and maintenance=backup and restore=Rrepair windows using system restore(top left).
If this doesn,t work, download windows malicious software remover,below.
http://www.microsoft.com/security/malwareremove/default.mspx
If that doesn't work, burn it.