Many times this is caused by a bad hard-drive, if you did not get a virus or had other issues before this.
How did you try doing the repair? With a disk?
You can get another hard-drive, replace yours and setup Windows clean on that drive. Then using an external USB drive connection or just setting up your drive as a secondary in the computer (if it's a desktop or a laptop with two drive bays) you can copy your files over to the new setup.