Computer Constantly Freezes!

One of the computers in my network randomly freezes. It does this quite often, about evert 10-15 minutes. It seems to be a hardware failure, but I’m not sure what it could be. When it freezes, nothing works and my only option is to restart the computer. CTRL+ALT+DLT doesn’t work, nor do the mouse or keyboard. Last time I used it, it froze in the middle of doing a scan disk (because it had just frozen before and not been shut down properly) and then when I tried to restart it, it wouldn’t start. I heard the fan blowing, but that was it. Nothing else, it just stayed like that. Do you have any ideas what might be wrong with my computer.
Thanks for your help!