Guys, here is my 2 cents..might be a shot in the dark ..Ok reformatting it should have taken care of the problem..now.reinstalling your o/s is fine and all the other recomendations are in order especially more ram..you can never have enough..If you don,t have a big hdd drive like 120gig or so to let windows manage the swapfile we stick to at least double your ram which in your case manully set to 256mb swapfile...

Ok my first question is ..since you sit on a network even with your firewall in place , my guess is that you get infected from somewhere on your network..have look at the traffic which you let through on the firewall profiles, and stop them one by one to try and determine which one is giving you the the infection..I can not specificly remember the virus name but i know a friend of mine also got infected and each time you restart and so fourth the file size gets modified up to a point that your drive is filled up or in your case your swapfile size..

hope it helps
cheers
vanman