Those videos aren't corrupting your computer unless you somehow got a virus in the process. Here is what I'd do if I were you.
1) Run a virus scanner.
2) Error check your hard drive Right click your hard drive > properties > tools > error-checking. Check both boxes and restart your computer. It'll take some time to run through but it will let you know if your hard drive is actualy corrupt.
3) Defragment - Same steps as step 3 but click Defragmentation instead of Error-checking
Honestly, the best thing you could do is reformat your computer assuming nothing is corrupt. It's a clean start at life, but you'll lose your videos in the processes of a clean reformat but it'll run like the day you bought it.
If you do all of that and are still not satisfied, buy a SSD. Keep in mind they cost more than a regular HDD. If you are still looking to keep a video collection, use the SSD to boot Windows and keep all your videos on the HDD.