This dose not mean that there is a direct problem with the GPU or CPU as you're describing. By what you have said, this makes me think this is a temperature issue. I would first check the temps of my CPU and see if thats what doing it. Have you overclocked it? If so, check the temps. If thats fine, I'm not very good with intergrated graphics. Your best bet would be to test your memory, because it could never hurt to
And try and get your hands on a stand alone video card so you could test the reliability of your intergrated chip.