1. Click the 'Start' button and then click the 'All Programs' button.
2. Click the 'Accessories' tab, and then right-click on the 'Command Prompt' option.

3. Click 'Run as administrator' from the menu, and then enter your administrator password into the field that appears.
4. Type 'sfc /scannow' into the command prompt and press the 'Enter' key.
5. Wait for the scan to complete and then restart your computer to clear the error.