I have a Dell Latitude 6520 and was having the same problem, corrupted local C: and I hope this will help, it fixed mine. Turn on computer and immediately begin tapping F8 (before logo appears), screen will appear and "Repair Your Computer" will be highlighted, click on your enter key on keyboard. Windows will load files and then the System Recovery Options screen will appear. On Keyboard Input Method click US and then click Next. System Recovery Options screen will appear again, on User name box choose "user", on password type in your log in password for your computer and then click ok. System Recovery Options will appear again, click on Start Up Repair. Repair will begin, when it is finished, click on finish.
This took care of mine and it's working great now.