Just bought a Compudyne 386 desktop at the thrift store and need help opening the all plastic case. The case has two latches at the top rear corners of the case and a case screw in between the latches. Spring the latches and remove the screw and the top back part of the case comes loose, but it binds in the middle to front of the case and won't remove. Any ideas? Thanks, Steve Phipps trs-80 at cableone.net