MOUSE OR JOYSTICK PROBLEMS
A known good mouse and joystick should be used to eliminate them as the source of the problem. If it is determined that the mouse and joystick are okay, the most likely causes are:
Mouse does not move, left and right mouse buttons okay, joystick okay:
EMI 1401 5.1 ohm resistor (supplies 5 volt to mouse). A2000 Rev.6 and up: F1 4 amp pico fuse.
8362 U4 (U201 A2000)
74LS157 U15 (U202 A2000)
http://home.arcor.de/kickstart/TKA/Tutorials/troubleshooter/a5kts2.gif :-D
