| It sounds like you have a serious spyware contamination. I suggest that you check to see: 1) That everything is running correctly, 2) That everything is updated, and 3) That everything is run and cleaned up.|
1) Click 'Start', 'Control Panel', then 'Security Center'. Windows should be set for automatic updates; your anti-virus should be running, and the firewall should be working.
2) Update everything. Windows XP Home should be using Service Pack 3. (If you haven't update Windows in a very long time, then it won't include 'Security Center' in the Control Panel, nor a firewall.) If you don't like the Windows firewall, then Comodo and ZoneAlarm have good ones.
Update your browsers, IE and Firefox; check their security settings; then just use Firefox. ;)
Update your anti-virus definitions. If your subscription to Norton's runs out, then I'd suggest a free anti-virus program. I'm partial to avast!, but Avira and AVG are good. (They're free to home users.)
Update Ad-Aware from SE to 2008 and get the latest definitions.
Additionally, you'll want another spyware program or two. They'll check for stuff that Ad-Aware doesn't. I like Spybot S+D, and Windows Defender from MicroSoft. You may prefer Spyware Terminator, Webroot Spy Sweeper, or Malwarebytes' Anti-Malware.
Also, get something to clean and backup your registry. I like CCleaner which is quick, and Glary Utilities which has more options.
All programs that I've suggested are free and can be found at download.com, though you may find them at tucows.com or filehippo.com.
3) Finally! Disconnect from the Internet, if you're using DSL or cable. Run your anti-virus, then the spyware/adware programs, using the thorough or deep cleaning options. Next, clean out junk/temp files; then run the registry cleaner after backing up. When this is all done, I'd suggest defragging your C drive.
All of this may take a few hours, but it will definitely clean up your system and make it run most smoothly.