This morning we had a problem starting our Intel iMac. It was turning on but all that was happening was the white power light on the front was lit up. I tried the usual things like
unplugging all the peripherals – nope
unplugging everything and waiting 15 minutes and plugging the power, keyboard and mouse back in and trying – again nothing.

After a bit of searching around I found a possible solution which I found worked. Basically it was to unplug everything, remove the ram wait a few seconds. Put back together and hey presto it was up and running again.