When important system files break, hardly anything on your machine remains working. Many programs won't be able to start and you will be flooded with error notifications and Bluescreens of Death.
Windows 7 has a function to solve that kind of problem itself. All you will need for the procedure is access to your machine and your Windows 7 installation disk.
1. Enter your Windows 7 DVD into the disk tray. Then run the command line by typing cmd in the main menu. Right-click the application and select Run as administrator to run it with administrative rights (alternatively, you can press Ctrl + Shift + Enter while cmd is highlighted).
2. Enter following into the console:
3. The system scan will be initiated and the broken files will be localized. This can take a few minutes. If broken files are found, they will be replaced by healthy ones from the DVD.
4. Perform a Windows update to make sure the new system files are up to date and reboot afterwards.
Thanks to Alexander Fox for this post!