Problems with SP2 and Yahoo messenger

I am running winXp on my dell laptop and started using a LAN at my school on
Thursday. Yahoo Messenger worked fine and ran my webcam as usual and i had no
problems. Saturday my computer decided it was time to download the SP2
update. Since then I have been unable to use Yahoo messenger with my web cam
because it tells me I can't use the webcam service with a firewall. I tried
turning it off and it didn't work. I tried going through Yahoo's site
http://help.yahoo.com/help/us/chat/w...ebcams-25.html and followed their
instructions but it keeps changing the "Name or IP" back to my computer name.
I am at school and the only way I can see my friends and family is through
our webcams. If anyone knows how to uninstall this god awful update, please
let me know. ,

Thanks in advance.