It sounds like you are infested with spy/adware and or viruses. Do you have a virus program? If not, get a free one from here http://www.grisoft.com/us/us_index.php
Download Adaware from here http://www.lavasoftusa.com/
Spybot - Search & Destroy 1.3 from here http://www.safer-networking.org/en/download/index.html. They are both free, but I suggest a donation to Spybot.
Update the reference files and run them. You will be surprised at what they find. Be aware, some programs have spyware bundled with them and will not work if you remove it, or you may be in violation of a licence agreement.
There may be other issues. If so post back. i can't promise to help, or even come back to this page, but will help if possible.
Professor Higgins (not really. just a nickname!!)
August 2004