Difficult to tell without a photo, but try this: Download a Linux Live distribution such as Knoppix (
http://www.knoppix.org ) and then try using that to boot your computer. If you still get garbled output, then it's probably time to be looking for a new laptop. You likely have a bad GPU, and that's soldered directly to the motherboard. If Knoppix boots up just fine, including a graphical environment, then you might be able to get away with just reinstalling Windows.