When playing games and on YouTube, my laptop scren will occasionally freeze. This is accompanied by a loud buzzing noise (which seems to be the audio stuttering - not sure). After several seconds the screen returns to normal and play resumes. Any ideas what this could be caused by?
Sounds like the GPU might be going bad or your video driver keeps crashing. Unfortunately, that is a bit harder to diagnose on a laptop. Make sure your video drivers are up-to-date. Also, download a program that can monitor computer temperatures of the CPU and the GPU.
Can you give us a full list out of the laptop specs, including brand and model?
Hmmm, Intel integrated crap. Honestly, and I could be wrong, it does sound like the graphics chip on the motherboard is going bad. However, we want to make dang sure first.
Google some HDD scanning software that will diagnose your HDD. Depending on the maker of the HDD, you can get one from that company's website (usually).
Also download Memtest86+ and run that for several hours. It'll test your RAM to make sure that the RAM isn't bad. You may have to remove a stick of RAM, as its best to test each stick individually. If you don't want to do that, I understand, and go ahead and run the test anyway. If you get any errors back, then it stands that you have bad memory (or a bad stick of it at least).