It sounds like the drive is dead or dying. I'd recommend connecting the drive to another machine (by USB if you have an enclosure) and copying off any critical or recently-modified files. (You can try to backup the entire drive if you like.)
Then run diagnostics on the drive. Most likely it will fail, and the solution will be to replace the drive. Then restore from a backup, possibly the backup you made above.
Caution: Since there's a possibility the drive is physically failing, if there is any data you care about on it, it is extremely important that you try to recover that data first. The drive may have very limited remaining life and every time you try to boot from it or 'chkdsk' it, you may be using up those precious minutes. After you've recovered any data you care about (or given up on trying) you can try to recover the operating system installation.