My 15 inch powerbook g4 1.67GHz has a broken keyboard. The keyboard will intermittently work about 10% of the time. Most cases it is unusable and I have to use a usb keyboard. Any idea on how to fix? I dont want to pay the $300 that the apple store is asking for such an old laptop. Would buying a replacement keyboard on ebay do the trick? is it easy to install? thanks in advance!!