dont take the glass out of a 20 year old door, never get it back in right, anyway dont think you can get at the lock that way,the screw that holds the lock in , is under the lock cover, the silver plate that covers the lock, if you take the 2 screws off the the lock plate cover you will see the 1 screw that holds the lock in the door, but to do this you need the door open,,you could try takeing one of the handels off, from the inside, and try grip the handel barr that comes out of the lock and see if it will turn with a plyers .. ect, if not call out a locksmith, and get him to open it, and replace the lock,
h, September 2012