From what ive been reading online, this could be cause by a hardware failure somewhere so look for any conflicts..can u manage to log in in safe mode at all?

im not sure whether you can just use any other cd apart from the bkup cd they shud have given u when u bought ur pc...apart from this all i knw is you can make ur own recovery disk providing u have xp running :S

Have u tried resetting the bios? (taking the battery out), sometimes this helps...(im not in best condition atm so plz forgive me if this didnt make sense...)

Regards,