I have a couple of ideas for you to try.
Load the Recovery Console and run "chkdsk /r". This will scan your harddrive and fix any file and disk errors. Doing this first helps to ensure that any fixes done later will be done in good areas on the harddrive.
If the system is still having problems, load up the system in Safe Mode and run "sfc /scannow". This will make sure that all your system files are as they should be.
Update the thread and let us know if this took care of your problem or not.
P.S. It's better only post a subject once. Since this topic is in two different areas, you'll have people that are giving different sets of instructions that may confuse you.