We use both of these programs with Vista and XP. We highly recommend them.
You can try them at No Cost
Registry Smart  and Repair XP Pro 100% XP & Vista Compatible
(Great programs) The most comprehensive system repair tools on the market.
 

Turn off Microsoft's phone home error reporting "feature".
Right click My Computer, select Properties, select Advanced, select Error Reporting and check the Disable error reporting box.

* The hottest Registry cleaning software on the Net today!

* Repair XP Pro - (Great program) The most comprehensive system repair tool on the market.

* Scan your PC for errors absolutely Free (Very good)

* If you use Google AdSense™ Read this page Correct Keywords can pay you more money

* Evidence Eliminator - Erase your surfing history total "privacy protection".

* Double the speed of your PC!Discover the secrets to speed up and optimize your PC in minutes!

* 100's of Very Good Assorted Free computer programs.