Hi,
If it turns out to be a virus and can't be cleaned/removed easily or has done some damage that's not easily fixed, I'd run a System Restore for a date prior to the date you think the virus infection occurred.
You'll find the System Restore on the following path:
Start - All Programs - Accessories - System Tools - System Restore
You'll see a Calendar with the bold dates being restore capable dates. Restore doesn't wipe data files, mail, etc., it just restores the system and program files back to how they looked at that point in time.
Danno