My advice would be to purchase an Intel machine, refurbished or new. Your Powerbook has a PowerPC processor, which is quickly becoming obsolete in the Mac world. In short, using a PowerPC Mac is living in the past. New software is not developed with PowerPC machines in mind, and more and more developers have stopped supporting PowerPC apps. I would spend the money you would otherwise spend on repairs, a Cinema Display, and a keyboard on a refurbished iMac purchased from Apple.