Try checking for bad sectors and errors in the PS3 Recovery menu.
1.Have your PS3 on Stand by (redlight)
2.Hold the power button until it go's red again
3.Hold power button until your hear 2 BEEPS then let go
4.Plug controller via USB Cable
5.Select "Rebuild Database"
6.Repeat and select "Restore File System"
[ame=
https://www.youtube.com/watch?v=_2YnGGUOJks&feature=related]YouTube - How to get the Recovery Menu on your PS3[/ame]