Try switching off the laptop by holding down the power button for about 10 seconds, then disconnect the mains lead and remove laptop battery (so there is absolutely no power to laptop)
next hold down the power button for about 30 seconds (to drain any residual power and clear the volatile memory)
now put battery back in and connect the mains and switch on.
This may clear the fault or instigate a 'Check Disk' (Chkdsk command) that will check the disk for errors.
Post back with what happens after you have done the above.