PS3 Error: "This is an invalid disc" & freezing

[Schrute Farms]

I have gotten the following errors in the last 24 hours:

1. "This is an invalid disc"
2. The system freezes during the PS3 menu
3. The picture freezes during playback


I thought I needed a software update, but my PS3 told me I had the most current updates.

I tried a quick format, then restarted the PS3. I tried another movie and I got the "invalid disc" error again.

The system played movies fine yesterday. Now my PS3 won't play COD4, The Prestige, Transporter, or Shooter. All give me the "invalid disc" error.

HELP!