Please help upgrading from xp to windows 7 almost complete when blue screen of death appeared. So computer shut down on reboot message appeared system shut down suddenly please insert disc to continue install. Nothing happened each time i inserted disc it was a continual loop of the same message. Turned the computer of now all i get is NTDLR missing press cntrl +alt+ delete. I am getting nowhere have tried re installing xp, reinstalling 7. Have changed the boot sequencing all to no joy.