If you're on Windows 8 or 10;
1 - On your keyboard, press "Windows Key + X"
2 - You should see a menu
3 - Click on "Command Prompt (Admin)"
4 - In the window that popped out, type in there "/sfc scannow" without the ""
5 - Wait for the process to finish
6 - Restart your PC
If you're on Windows...