Sudden crashing and freezing is often a sign of hard disk failing. The crashing would then be due to corrupted files; the freezing would then be due to the disk controller trying to read a failing sector over and over until it gives up.
If this is the case, a reinstall will accomplish nothing; in fact, it will probably fail during its attempts, as it writes to bad sectors.
Your best bet would be to find out the make and model of the hard drive, go to that vendors website, download and install any drive health app they may have, and run that ... but since you probably won't be able to install anything in the machine's current condition, you would need to remove the drive and connect it to a working PC -- and use that PC to test the hard drive.