Try a new HDD and see if that clears it up. I read you don't want a new HDD so maybe it's the end for this laptop. You could run Linux off some USB memory stick or CD/DVD but most folk relent on replacing the failing HDD. It's pretty cheap.
But some ask if a failing HDD can be repaired. My answer is not any longer. The cost to repair the HDD is north of a thousand bucks.
I have my Toshiba laptop for almost 3 years now.
2 weeks ago, I reinstalled Windows 10 for a fresh restart.
Yesterday, I downloaded Malwarebytes to scan my computer, It found some errors and viruses that I never thought of.
After correcting and putting the virus in quarantine, I was asked to restart my computer which I did.
The computer was abnormally slow, after the blue windows 10 screen, it took about 15-20 minutes before the welcome screen, Then 15 more minutes before the login screen, after I put my password it took at least 30-45 minutes to load the start screen. I couldn't open anything, when I pressed the home button the computer froze.
I then tried to reinstall windows again. Unfortunately it says "Windows cannot be installed on this disk, the disk may fail soon"
I tried a system restore, it failed saying that something about windows/app
I tried chkdsk C: /f /r /x which failed after taking the whole night.
I don't know what to do at this point I have important data on my hard drive, and I don't want to buy a new hard drive either.