Freeze-pause to react again or freeze-halt requiring power-cycle?
Any software, any time? Mouse (USB?) not responding? Does the Numlock key[1] toggle the NumLock light?
For Windows does Ctrl-Alt-Del bring up (eventually?) the task manager (also try Ctrl-Shift-Escape)? It might take time, but should pop up in a not-utterly-frozen situation eventually. If it gets you to a BSOD (or equivalent) it's something more, if it reboots it's maybe worse (memory access/management issue, IME). It's a freeze that does nothing until you power down/case-reset it then it's deep but maybe easily solvable.
There's a lot to go on. For one thing, we don't know the OS. And if it's Win10 I'm going to have to stick with "it works with prior versions" advice, myself, as have not touched it enough to know how much things might have changed.
Can we assuming you've got AV software, updated, may have done other malware scanning and have initiated/allowed basic disk checking, including that you're not down to your last few Mb of disk space, etc? Without eyeballs on the system, I think we need to flail about a bit before we're sure we know what problem needs solving. Other than system reinstall from scratch which I wouldn't suggest if it's maybe as simple as reupdating corrupted drivers or similar. If it gets that far, maybe you need a tech-guy to work on it for you, one way or another, but maybe that's for later.
((Ninjaed by three messages. Hopefully not stomping on anyone else's toes.))
(((edit: Ah, good. We're getting somewhere. Carry on!)))
[1] Or combo, in laptops, but I'm guessing it's not that from the bit about its bits.