can you open command prompt in windows? (Windows Key + R, then type 'cmd')
type: sfc /scannow and see if that helps.
If you can't get to command prompt, then try booting to command prompt (should be in the same menu as booting 2 safe-mode)
if that doesn't work, then you may want to try doing an OS repair
Boot to the installation disk, and after you select language click repair.