If you try to restart it several times, it will come up with soem more StartUp Repair options. I suggest you take the Command Prompt option and test the hard disk for errors by typing
chkdsk /r
then hit the Enter key.
That will send the system off to find any errors there are on the disk and try to fix them.
If that doesn't do the trick, go back into Command and this time type,
sfc /scannow
and hit Enter.
That runs the System File Checker which replaces any missing or corrupted system files. Failing that, you need to reinstall but psot back here before doing that.