Helping people with computers... one answer at a time.
Video uses a fair amount of processing power on a computer - that load could be overheating your computer.
My computer started crashing about a month ago every time a YouTube video is attempted to be played. Now, even if a web page is open which has on it a YouTube, the computer freezes and then crashes; no blue wall, no explanation, just a black screen and then I have to restart. I've done everything: virus updates; spyware; updated Adobe Flash; uninstalled Firefox; reinstalled. It made no difference if the YouTube is played on IE8 or Firefox.
In this excerpt from Answercast #4, I'll explore several possibilities that might be causing a computer to shut down suddenly when viewing online video.
Two things to look at might be overheating and drivers.
So a couple of things come to mind here for situations like this. The most common problem is overheating, believe it or not.
Playing video on some computers actually uses a fair amount of either CPU or graphics card processing power, which causes those devices to actually heat up. Sometimes, they can heat up so much that they become unstable internally and cause the computer to crash.
Now normally, a computer is designed not to have that happen. You've got fans running, blowing (hopefully) cool air through the machine, and so on. But sometimes, the fans stop working or the machine has a bunch of dirt in it that prevents the air from flowing through it properly, so that's the first thing I'd check.
Make sure that the machine's properly ventilated and halfway clean on the inside; the fans are turning and that they're not blocked for some reason. The other thing that comes to mind, it's a little bit more of a long shot, since this has been increasing for you over time. That's what makes me think of the heating aspect of this, but the other side of this coin is to look at the video card drivers.
You've done a lot of the things that I would have done already; checking for spyware, checking for malware, updating Flash, updating your browser, that kind of thing; that's all great. The only piece that's really missing there are your video card drivers.
It's very possible that they have some kind of an issue that's kicking in when you are attempting to play a YouTube video. So, my recommendation there would be to go to your computer manufacturer and see if they have updated drivers for your video card. Or go to the video card manufacturer's website and see if they have updated drivers for that video card. See if updating those helps the problem.