Posted Wed May 14, 2003 9:24 AM
When I bought a replacement screen for my GBA (the clear plastic protective screen mounted to the case, not the LCD itself), it came with instructions for removing the original screen. The instructions were a photocopy of the sheet that accompanies GBC replacement screens!
Regardless, the procedure was the same. When you buy a replacement screen from Nintendo via their website, they also provide a plastic hook with an adhesive pad. You apply the adhesive pad to one of the top corners of the screen, and pull on the hook until the screen detaches from the case. I guess the adhesive on the hook must be stronger than the adhesive holding the screen in place at those points.
If you got your replacement screen without the hook, though, then you may be limited to prying it off with something thin as was suggested above. In the alternative, you could open the case up and try to push the screen out from the inside, which might be easier.