PS3 Slim, had it for a few years. I was playing Black Ops 2 just yesterday; then I turned it of and back on again and it went to a screen saying exactly this, "The file system on the system storage is corrupted and will be restored." My only option is 'OK' and I cannot use o or triangle or the PS button (it shows the no PS-button use aloud sign). So I press OK and the restore starts. It then says 'Restoring... Do not turn off system.' the the loading bar then at the bottom it says 'After this operation has complete, the system will restart.' I then wait about 10 minutes and right when it gets to 100% done, it makes the 'download over' sound, and goes to a black screen. I no longer have access to controls or vision of the screen. HELP. (ALSO, I am forced to do this, I have no choice of cancelling it. When I try to turn it off, the power button on the ps3 doesn't work and I have to unplug it from the wall to turn it off.)
I don't have time to continue reading the comments to see if anybody has already given you a solution, but do not replace the hard drive, do not send it in for service, and do not buy a new system. That will not fix the problem, and it's an easy do-it-yourself procedure. The more you download (or remove), or continuously operate, the more it can corrupt your drive, to a point where your system's normal operation may not recognize the corruption.
What you do is make sure your PS3 is turned on, eject the disc, then hold down the power button until you hear 3 different beeps, about 3-5 seconds apart, then release.
Hold it down again to turn on, wait for 3 beeps (the same way), then release again.
Do it one more time, and the 2nd or 3rd beep should be a double beep, then release.
Connect your Dualshock 3 controller via USB, then follow the steps. I don't remember if there are any you have to select, other than pressing the PS button before each selection, but when you come to the 6 different choice selections, you want to go with option 3, to restore the system (this will NOT wipe your files off). Depending on the strength of your corruption it may take a while. After it finishes the system will automatically restart back into normal function. Disconnect your controller and go back to using it wirelessly. If you continue to have freezing problems, or system shut offs after this then I would contact customer support (U.S. 1-800-345-7669) and let them know the steps you have attempted. Good luck.