iFixit

Use your fingernail or the edge of a spudger to flip up the retaining flap on the UMD drive ribbon socket.

Be sure you are prying up on the retaining flap, not the socket itself

Use your fingernail or tip of a spudger to push both sides of the black retaining flap on the UMD laser ribbon socket to the right.

Use a spudger to gently pull both ribbon cables straight out of their sockets.

Flip the PSP 300xc over and open the UMD door.

Using a pair of tweezers, grab the small rubber square between the metal UMD brace and case, and lift it out of the PSP 300xc.

Repeat for the rubber square on the other side of the UMD door.

Slide the UMD brace toward the top of the UMD door until the brace disconnects from the door. Remove the brace.