If you're in a corporate environment where you do not have administrative rights on the machine, you should have a conversation with your friendly IT person; however, I'm guessing that's no the case.
If it's your home machine and you're an administrator, it's a good indication that the filesystem is corrupt. It's not really great news, sorry.
First things first, if you have anything important on the machine, now is an excellent time to back it up somewhere. Removable disk, web storage, whatever. When the filesystem starts getting wonky, it could just be a poorly timed power outage or something, or it could be an early indication that your hard disk is going to bite the dust soon. Having lost my fair share of drives, I'd recommend taking the warning as a gift and make a backup. It's way less painful than the alternative.
Once your valuables are secured, and your seat is in the locked and upright position, scan for and fix anything wrong with the filesystem.
Check your hard disk for errors - Windows 7:
https://support.microsoft.com/en-us/kb/2641432
At that point, take the nuclear option and manually purge every bit of Flash Player from the system.
(Note: These instructions are for Win7 and below. If you're on Win8 or higher, let's talk more before you do anything.)
Performing a Clean install of Flash Player on Windows:
https://forums.adobe.com/thread/928315
My guess is that you're going to arrive at a step that you can't complete because you lack permissions to do it, although you *do* have permission.
If it's deleting a file, usually a utility like Unlocker will fix it for you, at which point you can delete the file and complete the removal process. That was probably the damaged file. If you couldn't clean it up as admin, our installers weren't able to touch it either.
Unlocker - Free download and software reviews - CNET Download.com
If it's a registry key, you have larger problems. There are commercial third-party utilities that purport to make magic registry fixes, but Windows includes it's own registry checker and repair tool that's already not fixing the issue. I'll leave it up to you to experiment with those if you want, or whether you just want to do a complete reinstall of the OS and applications. Either way, something is wrong with the underlying OS. Personally, I tend to be skeptical of the aftermarket utilities, and if it's been a few years, you'll probably be surprised at how fast the machine is after doing a fresh OS installation.
Hope that helps.