Make sure you type it in correctly. If you are, you're missing some critical files on your computer.
Doesn't work, yet.
Maybe changing my OS be a good idea.
Thanks for your guidances.
If all of our suggestions, including Neo's have failed, then your last resort would be to re-install your Windows. But make sure you have the valid keys for it.
I have already reinstalled it, but doesn't work.
Click the repair button in the trouble shooter
It doesn't solve the problem.