I have just been giving a G4 and trying to figure out what is wrong with it.

When i plug it in and press on button sound comes on nothing on the screen.
Took out ram and seams to make no difference.
Took out wireless card and keyboard and no difference.

Took disk to copy off files but when i plug it into mac book pro says it can not initalize it and that it is 2.2tb but its only 30gb.

What do do next? Is the disk and main board broken?