I have a friend's computer which has Windows 7 Ultimate, He went into the registry and delete it and the problem now is that the dvd room won't be detected, I updated the drivers but still will fail, I can't install his printer cause the Hp software won't detect the printer's usb. I can connect an external USB with no problems. I was going to do a repair on the system but the DVD room won't work. How can I run a repair using a USB? or what would be your advise on this problem?