I have a Compaq Presario S4100NX that would usually pop up some kind of image that looks like a transparent checkerbroad that fill up the whole screen, then freezes the whole computer up. I would then turn off the computer and restart it again. But as I restart it, the computer rufuses to start back up again. I would have to wait for a couple weeks later for the computer to go back up and running, but then the same situation occurs again. Any suggestions? Thank you.