Is my iMac dying?

[yliu]

So I got an early 2008 iMac which I have been using daily since the purchase. Even though I got a new MBP, I am still using it when I'm home.

However, recently it started to restart for no reason. During usage, it would freeze and within a few seconds, the screen turns off and the computer automatically restarts.
I could include a crash report next time it crashes.

Does anyone had the same experience? What is it a sign of? Dying HDD? CPU?

 

[Mr Rabbit]

The mid 2007/early 2008 iMacs seemed to have a decent amount of power & spontaneous issues.

Once your iMac restarts does it get stuck in a loop where it shuts down and restarts every few minutes or so? Or will it just shutdown and restart once or twice a day?

The DC SATA cable in these iMacs seemed to be faulty and I believe a revised cable (same part number though) was eventually fed into production and the restart loops were resolved. The telltale symptom was as I mentioned earlier, the iMac would suddenly restart and then consider to do so in a loop until you unplugged it from power. You could eventually reconnect it to power and get some use out of it until the issue popped up again. The DC SATA cables were/are relatively cheap but it's a very labor intensive repair as it's essentially the last part inside the machine. You basically remove the glass, bezel, logic board, hard drive, optical drive, power supply, fans, stand and chassis before having full access to the cable.

It could possibly be failing RAM as well. Has it ever beeped (not the usual chime) when it restarted?

 

[yliu]

The mid 2007/early 2008 iMacs seemed to have a decent amount of power & spontaneous issues.

Once your iMac restarts does it get stuck in a loop where it shuts down and restarts every few minutes or so? Or will it just shutdown and restart once or twice a day?

The DC SATA cable in these iMacs seemed to be faulty and I believe a revised cable (same part number though) was eventually fed into production and the restart loops were resolved. The telltale symptom was as I mentioned earlier, the iMac would suddenly restart and then consider to do so in a loop until you unplugged it from power. You could eventually reconnect it to power and get some use out of it until the issue popped up again. The DC SATA cables were/are relatively cheap but it's a very labor intensive repair as it's essentially the last part inside the machine. You basically remove the glass, bezel, logic board, hard drive, optical drive, power supply, fans, stand and chassis before having full access to the cable.

It could possibly be failing RAM as well. Has it ever beeped (not the usual chime) when it restarted?

This restarting had never happened until now, so I doubt I had a bad cable. It is not happening in a loop. It just once a every dew days...

It also had no beeping while restarting. The restart is just like a normal restart, except there is a screen saying that my computer was restarted because of a problem.

 

[Mr Rabbit]

But you do see the screen freeze just before it restarts?

The next time it restarts check your system log in Console, search for "Previous Shutdown Cause" and paste the activity a few minutes before and directly after the results into a reply here.