Fast24! £27.50 1mb, £37.50 2mb click here
Turn off your modem (router?) when your not using it. If it not on, they can't get in!
Get a decent AV. Get a firewall (Xp one is rubbish)
click here spybot click here Adaware
click here spyware blaster start page guard click here
Clean you system with spybot and adaware. Then add spywareblaster, and startpage guard (also immunise in spybot)
Download all, install, update, run.