I have a 2003 G4 PowerBook 12". It has 1.25GB memory, running version 10.4.11 with a 1GHz processor. My problem is it will intermittantly freeze, then a box rolls down the screen and in 3 languages it says "You need to restart your computer. Hold down the start button for several seconds." No reason is given about what the problem is. Any suggestions? Did a memtest and it said everything was fine.