I believe I heard of this before. I have the 80 GB Core (No PS2 Backwards Compatibility) so I never encountered it. There is either two things you can do:
1 - Rebuild the System's Database.
2 - You'll have to pay Sony $150.00 (If you have no warranty) to have it repaired/replaced with another 40GB.
(How to get access to service mode
1. Make sure the PS3 is turned off,
2. Press and hold the power button on the PS3 it will power on then power off.
3. When it's off press and hold the power button again until you hear two consecutive beeps.
4. It will ask for the controller to be connected via the USB cable,
5. Turn on the controller and you will have access to the menu.)
PS3 Model - 80 GB/Non PS2-BC
PS3 Version - CECHL01
Modification(s) - Official Firmware 4.00
Purchased - March 27th, 2009
PS2 Model - Slimline/SCPH-77001
PS2 Version - V15
Modification(s) - UlaunchElf 4.42/Free MC Boot 1.8b
Purchased - April 16, 2007