I would take it from what you've posted that either the video chipset on your motherboard (which is integrated as I used to own a laptop in the same series) or your entire mobo has shot. If it's still under warranty what I would suggest is removing the HD and putting it in an external enclosure to copy the data off to a backup then reinstall the HD and send it off for warranty work. I had an amazing experience with Gateway CS so you should have no issues there. If it's not under warranty than I would suggest removing the HD so you can keep it as an external drive and simply buy a new laptop and then copy your data to the new one.
I would also suggest if you're going the route of a new laptop that you buy a secondary external backup drive and make at least a weekly backup of your important data. That way if anything goes wrong you're not scrambling.