I recently had the same issue with a box here at work. Thought it was blaster but turned out to be some spyware "vbouncer" or some such thing. Ran the most recent Ad-Aware and Spybot S&D and all was fine. Running the latest McAfee Stinger found nothing.
Just my $.02
BTW, :wave: Welcome To TechSpot! :wave: with your first post.