I can't say what the problem is offhand but try booting into the alternate
boot menu using F8 when starting up and first try "last good configuration"
and if that does not help try booting into safe mode. If safe mode works you
have a problem with a startup program, application, or driver which could be
virus related and a tool like Msconfig can help troubleshoot by doing
selective startups. If nothing helps it could also be a hardware problem,
usually related to bad memory, bad power supply, or overheating CPU. Try
booting from a bootable floppy or cdrom to see if you can do that. Possible
repair if you can not get into the operating system would be to try to use
first fast repair by booting from the install cdrom or to do an in place
upgrade of the operating system by booting from the cdrom which will require
you to know the product code and also reinstall first the service pack and
then all critical updates. The links below may help. --- Steve
http://support.microsoft.com/default.aspx?scid=kb;EN-US;238359
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q292175 -- select
repair option AFTER user agreement