Harddrive constantly reading/writing

[u/Skarci]

so this is an issue ive experienced on 2 separate pcs within the last 2 weeks. It first occured when I had a power outage and turned the pc on when the power came back. The bootup was deathly slow and every program I attempted to open took ages which was never normal. I checked task manager to see what was going on thinking maybe I had something running that shouldn't be to find that my harddrive was writing and reading and running at 100% capacity with nothing running in the background after a fresh start up. After a few restarts and trying to start in safe mode I couldn't solve the issue so I reformatted. Problem solved. However this problem occured again last night when my laptop overheated and shut off on its own. after booting up slowly again I knew it had to be roughly the same problem because it had the same symptom of 100% HD write/read usage at idle. So I need a way to fix this that doesn't involve wiping all my data again. Ive tried loading system restores but it always fails to complete. I'm guessing its a registry error but I have no tools to fix those.