Answer to: The Mac pro overheats and doesn't boot.I have the same problem with my MacBook Pro! It doesn't boot past the blue screen, on its own, but it boots with the Installation disk. I did the Repairs and the Verify, with no problems found, but the Boot with the D key for Diagnostics (with extended testing on) cannot go past (the second letter 't' in testing) 2/5 of the blue line, while 'testing memory', I switched the memory cards (2x1G) around but same result. Appreciate any advice. Mario.