I have been given an HP laptop to look at, originally the sound was not working so updated drivers and rebooted laptop, on reboot it would not boot up. I have tried booting up from recovery partition (F11) but it just black screens, I have tried booting up from Vista disc but it just comes up with the first screen with copying files along the bottom and then it black screens. Sometimes it willl restart, I will press a key to boot from cd, it goes through copying files with the white progress bar along the bottom and the stops with a blank screen or restarts. I have tried the same with a Win 7 disc which does the same but stops on the next screen with "starting windows" displayed. I have run memory checks and disc checks and both were fine. This has me puzzled so I am hoping you guys have a clue whats going on here.