If you go to START, RUN, and type --> msconfig and go to the far right button...On that list, id almost say that id guarantee the problems might be there on start up...Untick the boxes of the related programs and Apply, and OK, and Restart.
Of course, if they are not in there, then you could enable XPs built in firewall.
Otherwise, use all the links above and the Hijack this experts
Dan