Service pack 2 problems

Hello, I installed XP service pack 2 and the trouble began. 1. my computer will nolonger stand by or hibernate. the only way to shut it off is hold down the power button. 2. picasa 3 is totally corrupted and 3 tries to uninstall and reinstall have not helped. 3. I can;'t uninstall service pack 2, have tried control panel and restore. don't have xpcd to i can't do it through the registry. I have recover discs, but don't want to lose some of my programs. Suggestions please!