When I turn the computer on, it comes on fine but usually before I can do anything, the screen goes black and the message "monitor is going to sleep," then the entire computer shuts off. My power settings are all set to "never" shut off or go to sleep. The computer is Hewlett Packard desktop PC about 6 years old and running Vista. Worked great until a few weeks ago. Have done restore to previous setting several times but problem persists. Also, I have backed up my pictures, videos, e-mail and documents on an external hard drive, but can't locate them when I search. Everything looks to be compressed or something. How do I open them to see what is there? I am thinking of restoring the computer to factory settings, but don't want to lose anything personally valuable. Any help appreciated. Thank you. Shirley