PS2 Lens or Laser???!!! HELP!

I bought my PS2 Modded from Pakistan, its been about a year now and till last month my PS2 stopped reading Originals or Copied DVD Games!!!!! i tried all my games and none of them are working!

What happens is that, when i switch my PS2 ON while a Copied or an Original DVD GAME is in the Disc drive, it loads and says "Sony Computer Entertainment" and then waits for a bit while showing all the blocks and shit (its propably reading) and then goes to the Browser and System Configurations screen!!!!!

I dont think its the MOD CHIP, i REALLY think its the Lens or Laser!

CAN SOMEONE HELP?!!!!! IS IT THE LENS OR LASER OR MOD CHIP!!!