System freezes during shutdown in WinXP. HELP

[bigrash]

Help. I just installed Winxp yesterday, and now if I try to shutdown my system just freezes when it says "windows is shutting down". It was fine yesterday. The only files that I downloaded so far are just basic files like winzip, yahoo messenger, aim, divx codec.

I know that the cd that I installed from is not bad, because my friend has no problems with the same cd.