Possible corrupt files needing a restory to factory default or the hard drive is failing.
to check the HD. Right click on C drive and select properties/tools/error checking, check now and make sure automatic fix files system errors and scan for and attempt recovery of bad sectors are ticked, click start it will tell you it will check the drive on next boot. Note: it can take a while to scan the drive depending on the size. If it finds faults with the drive it will take longer, if it finds too many faults it will freeze.