Have you tried to reinstall windows (get the computer back to factory settings)?

I did that with my niece's laptop and it was (almost) as good as new. It was certainly faster and didn't freeze any more.

If you need any help with it let me know :)

Or maybe, as a first step, install the program called C Cleaner and let it clean up your computer.

https://www.piriform.com/ccleaner