OK Folks, need some help here. Late 2009 iMac, 10,1 Core 2 Duo, 3.6 GHz, running Snow Leopard, the original software that came on it. It constantly locks up, anywhere from 10 to 30 minutes after I turn it on. Even if I am not doing anything on it, just turn it on and let it run, it will lock up. On rare occasions, it will run for a few hours, as long as I don't use it, but that's very rare. When it does lock up. Opt+Cmd+Esc does nothing. Also, if the hard drives go to sleep, nothing will wake it up, not even the power button. I have to power it down with the power button, and turn it back on. The hard drive fans are not running, but the temps never get above about 49C. I have already reloaded the software, from disk, after a complete erase. Before I reloaded it, I ran disk verify, and it showed a lot of errors. I booted from disk, and repaired it, with no improvement. That's when I decided to reload the software. The first time I reloaded, it failed, but it worked the second time. I have run Disk Verify again since the reload, and it says it's OK. Any ideas? Power supply? HDD? Thanks in advance!!