I have a 2009 27" i5 iMac. For few months now, there was a significant delay after I press the power button to machine to power up. Few weeks ago, I had a power outage and aftwards it woud not turn on. Things I tried: - Resetting SMC - Leaving it unplugged from the wall - Leaving it unplugged from back of the machine - Holding down the Power button while plugged in - Holding down the Power button while unpugged - Leaving it unplugged with RAM out About an hour after, it mysteriously powered up. Yesterday, I had another power outage. This time I tried the same things, but did not power up for about 6 hours. Today, I had to unplug it after shutting down to switch power outlets and now it won't boot again. So I have to wait for it to mysteriously do it's own thing. Every time after it powers up, it works without any issues. What can cause this? Could it be a bad PRAM battery?