Troubleshooting a computer that shuts down when watching full-screen videos often involves either fixing problems that cause the computer to overheat during video playback or repairing software problems that cause the computer to crash. The first step to troubleshooting is determining if the root cause of the issue is related to hardware or software. Some video files may be corrupt and cause crashes during playback, so it is also advisable to determine if the issue occurs only with specific videos.
Full-screen video playback is a computationally-intensive operation that can cause computers to overheat, particularly if they have older processors and video cards or are attempting to play very high-resolution video. Computers that overheat eventually shut down from a computational error or due to protective features incorporated into the computer's hardware. It is possible to determine if a computer is overheating by using software programs that monitor the temperature of the processor and video card. A computer that overheats when playing video also often makes excessive fan noise when about to shut down, though the absence of fan noise could indicate that the computer's fans have failed. Many computers overheat due to excessive dust that blocks the free flow of air through the computer, and it is often sufficient to clean the computer's case and exhaust fans, which can resolve the problem.
Problems with the drivers that operate a computer's video card often lead to crashes during video playback, as do bugs in the video playback software itself. If there is no obvious overheating issue, the next step is reinstalling a computer's video card drivers and any software used to view videos that cause the computer to shut down. In rare cases, physical defects in the video card can causes crashes during video playback, in which case the card must be replaced.