Windows turns off and on for an hour or more. Where could be the problem?

Question

Windows

Before that, I talked about updates. Now it's just a gray screen. Windows 10
A couple of times I just had to turn off the computer.
I think the hard drive might break.

Answer 1

Most likely the disk - it can be stupidly faulty, or too slow for such a load, or simply filled to capacity.
Other reasons are also possible - lack of RAM, weak processor, poor cooling, faulty hardware, buggy software.
Or all of this in combination.
It is impossible to say for sure without diagnostics - see the SMART disk, processor load, temperature, memory usage. Make a load trace to understand what exactly is taking the longest.