Hope someone can help me here...

I am currently running WinXP on a Celeron 2.2 gig system.

I recently upgraded to WIN XP service Pack 2. Since then I have been unable to keep my original home page. Everytime I change it, it resets to www.msn.com. In addition, under internet options/connections/settings (and /LAN) it keeps reverting to using a proxy server even tho I change it to use automatic settings. Any Ideas on how to fix this?