i would get the scan tool for whichever company made the drive and do a scan. assuming you’ve actually let it run to correct whatever disk errors there are, it’s likely that since it keeps happening your slowness may be a hard drive problem.

What generation i5? What version of windows? How much ram? How did you reinstall windows? Is this a built pc or name brand?

What do you mean by disk check?

If there are problems with the drive that could explain the bad performance.

You might find the files show up in malware bytes and it might be able to remove them.

Also if you can find them in the task manager, if you can kill the processes there you might be able to delete the files manually.