Using DISM to repair windows from the install disc:
Assuming d: drive is where the cd/dvd is
launch cmd prompt as administrator
mkdir c:\mount
DISM.exe /mount-Image /ImageFile:d:\sources\install.wim /index:1 /mountdir:C:\mount\ /readonly
make sure this results in:
Mounting image
[==========================100.0%==========================]
The operation completed successfully.
then you can run
DISM.exe /Online /Cleanup-image /Restorehealth /Source:c:\mount\windows /LimitAccess