I've seen talk of the iMac G5 rev a recall that no specific cause was listed for. Well I can confirm its the same issue as the Dell recall (bad capacitors). It started with odd graphics glitches then ended up where the machine would not completly boot. The tech at the apple store opened it up and you could see the bulging capacitors. Here is the apple support page on it - http://www.apple.com/support/imac/repairextensionprogram/ The repair is a logic board and power supply replacement.