Also you should run the disk check utility on your C Drive.
Go to My comptuer ---> On the C: Drive right click and hit properties -->TOOLS tab --> Check volume for errors. ---> tick Automatically fix file system errors and click START
The system will tell you that it can't run it, but will run it upon rebooting. Tell it to schedule to run at next reboot, and reboot the comptuer.
This is how you run CHKDSK without bumping into the command prompt