If your Windows PC system is error or corrupted, you can repair it by using Windows Resque Disk or Windows Installer Disk. Usually the fixer is included inside the Windows installer disk. Follow these method:
Insert Windows CD, boot from Windows CD by load-up the system from CD-Rom, wait until it finished load the contents inside the CD.Press Enter if there is a dialog to enter to the EULA page. Press F8 to enter the repair mode by aggreing the EULA of Windows, wait until the Windows Repair find a lost or corrupt (broken) system file, then the Windows will fix the system file by itself. After it sucessfuly finished, press 'R' to restart and don't forget to load the system back directly to your harddisk.
It's recommended to make a system restore after the computer is sucessfuly fixed.