iMac not powering up and shutting down

[MonicaBrown]

Hi, I need some help. When I switch on my 27" iMac all that happens is it goes into the powering up screen, white screen with the apple symbol and a progress bar running underneath it and the grey spinning wheel spinning. Once it gets all the way through the progress bar (takes about 10 mins) the computer shuts down. I can't get past that screen. I have unplugged everything, rebooted the wireless connection etc. Not sure what else to do? We did have a brown out with our power on Monday night and we were off for 6 hours but I used the iMac on Tuesday night with no issues. (Brown out is limited power supply). Help???

 

[chas_m]

Power supply could be going, hard drive could be going, logic board or graphics card damaged by the brown outs ... There's no end of possible explanations. Take it to a shop.

 

[chscag]

It would help if you provided more details about your iMac. Year and model? And version of OS X? Also your location. Brown outs or power line spikes are detrimental to any electronic device especially a computer. It does sound like it may be a power supply problem and as advised it's best to let an Apple tech look at it. Also if your area experiences brown outs, it's best to use a line leveling uninterruptible power supply (UPS).

 

[ron4mac]

Here's a discussion that may help: https://discussions.apple.com/thread/2677220?start=0&tstart=0

Hope you have a backup!