Try booting into safe mode and running system restore. If that does not work you can look for help here - http://www.microsoft.com/windowsxp/expertzone/newsgroups/reader.mspx?dg=microsoft.public.windowsxp.general or here - http://www.microsoft.com/windowsxp/expertzone/newsgroups/reader.mspx?dg=microsoft.public.windowsupdate&lang=en&cr=US
will restoring the computer kill everything on my hard drive?