iMac Intel 21.5" EMC 2308 will not turn on

I have a 21.5" late 2009 iMac that will not turn on. Pressing the power button gives no response (no chime, no lights, no fan). It has apparently been having occasional issues turning on (it's my husbands; I wasn't aware of this issue). It was shut down normally this morning then left unplugged for several hours (we needed the power strip elsewhere) and now it will not turn on. I swapped power cords with my iMac (same model), held the power button down for 10 seconds, and also reset the SMC (something I did last month as the fan was going in overdrive at one point). Nothing changes. Apple support recommends bringing it in to be looked at but also suggests locating a third party computer repair shop since Apple discontinued hardware services for this model.