Hey guys, I have a 24" core 2 duo 2007-08 Alum Imac with 4 gb memory. I am having trouble getting it to start. Last week it woke from sleep and was locked up, tried restarting just hung at the apple gray screen endlessly loading. Checked extended hardware testing nothing found. Finally got it to boot using the OSX install disc. Then last night it acted up again, just using Safari locked up with spinning beachball. Tried restarting countless times no luck this time after awhile at the gray screen a crossed out circle showed up. Did the extended test again, nothing found. Would not boot from OSX disc either. Unplugged for the entire night. This morning I could only get it to boot with the OSX install disc and everything is fine. It seems like it won't boot from a wake or restart but once you get it going it will work until it either locks up or has to restart.