Maybe somebody can help me: I have a G4, 3 years old, OSX 10.3.5 which does not boot any more. Exactly, the boot takes place but finishes with the light blue screen, only the cursor is visible. No action possible neither with the keyboard, nor with the mouse. Apple service center claims that the mother board needs to be changed (hundreds of $ !!!) . Does anybody know something about this kind of failure? Is there a cheaper way to fix it? Thanks in advance for any help.