Hi All. My primary machine went down today. Came home from work, went to wake it from sleep, it was unresponsive, black screen, power light constant. Checked all connections, tried powering off, waiting, reboot, grey pinwheel on boot from HDD. Tried booting from OS install DVD, same issue. Removed all extra RAM, HDD's. Left standard ram and standard drive blank in computer, tried to boot from SL install dvd, hangs at same point. You can hear the DVD spin up, the pinwheel spins and then hangs after a while. I have tried a SMC reset. Zapping PRAM etc.