The PSP Uses UMD's they are basically very similar technolgy to a CD-ROM or DVD, which means, your drive may not function becuase of the following reasons:
1. It Needs cleaning
2. The Laser is mis-aligned ( See service tech )
3. The Firmware version of the psp is very old and the discs you are using is very new
4. The Disc(s) you are using are dirty or have scratches
5. The Operating system has been modified via the firmware and is cause problems,
6. A Manufacturers fault.
Tristan Gallagher, December 2007
