Have you taken all the ram off the motherboard? One of the sticks is the chip ram (probably a 2meg stick) I bet the machine won't do much without it.
Are you using a monitor on graphics card or the video output? Have you tried plugging it into a TV and seeing what colour screens you get? (Red means duff chipram but indicates power supply problems as well)
Are you sure your mouse works? (seeing as you are using it to test for problems)
Try putting a small ram stick in the fastram slots on the motherboard just to see if it works then. (I think the largest you can use is 4meg sticks)
