Try restrarting in Safe Mode, this will clear some caches. When you do ensure all perihperals are unplugged. You could have a peripheral that is creating a problem. Also as long as you have been backing up even if the machine has failed you are fine, you can restore from your backup. If you have not been backing up you may be in for a very painful lesson on why backup is critical.
The problem is that it will not shut down. I hold the power button but it just seems to put it to sleep because when I hit it again it makes sounds like it is waking up as opposed to starting up. It even does this after unplugging it. I know it is on because I can hear it running and as I said, it took a CD when I put one in the optical drive. It is just sitting in there with the sleep light fully on doing nothing. Fortunately I do have a back up. Assuming that Super Duper has kept its schedule I should have one from this week. At the very least I have one from October when I checked the schedule.
As old as your iMac is, have you cleaned out the dust? Dust buildup can lead to over heating issues. Remove any and all things plugged into it including the power cord, Remove the RAM access grille. Vacuum all openings starting with the RAM access area (air intake). Vacuum all ports and plugs, DVD slot and the opening across the top of the rear of the body. Blow compressed air through all your openings and vacuum again to remove any dust you loosend. Reinstall the RAM grille. Plug in the keyboard and mouse if not blue tooth. Insert power cord...
You are now in a perfect position to do a
- Shut down the computer.
- Unplug the computer's power cord and ALL peripherals.
- Wait 15 seconds.
- Attach the computers power cable.
- Wait another 5 seconds and press the power button to turn on the computer.
- It is the 5 second timing that initiates the reset.
In addition to doing a SMC Reset (do a couple for insurance) I'd also recommend resetting the PRAM. Instructions for that are in iMac SMC and PRAM reset.
If the machines restarts successfuly then make a backup using Time Machine and/or a bootable clone using SuperDuper or Carbon Copy Cloner today!
OK I couldn't do any of the above because my computer would not turn on. I've since found out that it was messed up because the RAM became unseated somehow. Not sure how that happened but the computer is back to running as good as it can. It is a late 2007 so it is a little sluggish with some apps that hog up a lot of RAM. We ordered up one of the new iMacs because it is time. Just wanted to give you all an update so maybe this info can be passed on in the future.