21.5-inch iMac (late 2011) will not turn on.

My iMac went to sleep (as I normally allow it to do at night), and the next morning it would not turn on at all. No startup screen, no apple logo, nothing. I do, however, hear the fan very slightly. And every once in a while I will hear the disc drive as if it's trying to eject a disc, but after that, there is no activity.

I unplugged the iMac from the surge protector and plugged it back in, nothing. I plugged it directly into the wall and tried to turn it on, nothing. I still hear the fan, and the disc drive still tries to eject a disc occasionally (I'm not sure if there is a disc in there or not).

We did have a power outage a few days ago, but (1) it was plugged into a surge protector, and (2) I have used the iMac since then.

I searched the forums, but most solution says to perform tasks that I can't perform, because it will not turn on. I have tried resetting the SMC:

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Shut down the computer.

Unplug the computer's power cord.

Wait fifteen seconds.

Attach the computer's power cord.

Wait five seconds, then press the power button to turn on the computer.

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I would post the OS, but I'm not sure what it is, as my computer will not turn on. I know it's a version of Lion, OS X 10.7 (but I did not install the latest update yet).

Nothing has worked. Any help would be appreciated. Thanks!