Hi A friend of mine has a G5 iMac that won't start. When you press the powerkey it tries to start, the power light glows, the screen goes grey and after a while the fans start whirring. Occasionally (twice in the past couple of days) it has started up, but it froze after a while. Other times the apple logo appears and the gear wheel starts turning but then it freezes. I have tried booting from DVD, holding down the shift key and have taken the back off and pressed the wee button on the board. Since my friend has the same model of iMac as me (they were bought at he same time and place) i tried the RAM that I took out of mine when I upgraded. None of these thing worked, and my TechTool DVD is stuck in it... Any ideas?