You don't mention what if any anti virus you have, so I'm assuming none. Install and run the following:- avast! anti virus click here and Spybot S&D spyware killer click here That should clear out any virii that you have left, plus any spyware. (If you do have anti virus, don't stick avast! on top. Two AV progs isn't a good idea.)
Then add a firewall like Outpost click here this gives you more control of what your PC does when online.
You say you deleted Blaster, did you install the security patch aswell ? if not it'll just come back click here .