I have an HP 2.0GHz computer running on XP. I came home one day to see the computer showing the Blue screen of death. Upon rebooting it took me to the reboot screen with options for safe mode, last known...etc. None of these work. They all get to the Logo screen then restart the computer bringing me back to the safe mode reboot screen. I have run all diagnostics and even the a memory test. Everything checks out fine. Any suggestions?