One of the most common issues experienced with the PlayStation 3 is a system error due to the console's inability to read games or discs. Luckily, there are some fairly simple fixes you can try to your game console up and running again.
This tutorial will teach you how to fix your PS3 if it won't read discs.
How To Fix Your PS3 Disc Reader
It may seem obvious, but one of the most common reasons for a console's inability to read a disc is disc damage. Check both sides of your disc to make sure that it is not scratched or damaged, and clean your disc carefully using a microfiber cloth. Once done, reinsert your disc into the console and attempt to launch it again.
Another common problem with disc recognition is having your console set to an alternate region. Different disc formats may not be recognized by your PS3. Launch your PlayStation 3, and head to Settings > System Settings > Default Settings. Verify that your region is correctly set and that it is compatible with the disc that you're trying to play.
If the above methods don't work, you can also try troubleshooting your device. Remove any disk from the drive, and put the device in standby mode. A red LED light will indicate the state of your device. Next, press and hold the On/Off button until you hear two beeps, followed by a double-beep. If you do not hear a double-beep, repeat the process. If done correctly, your device should launch to a menu. Choose the third option, and follow the procedure to reset your device.