I turned my PS3 on and it greeted me with a message saying that I hadn't turned it off properly last time (although I totally had) and that there was corrupted data on the hard drive. It suggested that I reformat it, which would take 2 or 3 hours. I said no and watched a DVD on the system. I turned it on again now and didn't receive any warning. Does that mean there's corrupted data on the drive and I won't know until I play a game and it strawberry floats me over, or that maybe on the off-chance my PS3 was lying to me and everything is fine? (I know it's probably unlikely, but I live in hope)
I'd start backing up your saves if I was you. Just to be on the safe side. Then again, PS3 has no games so how could you possibly have any save files anyway