iMac won't start up after lightning strike

Major lightning bolt strike outside our house. Brilliant white flash with what seem like sparks...No outside or inside damage. Have a lot of electronics....While we did not loose any power, we lost internet, security cameras, HVAC controls, wireless lighting, Router all went out, all came right back on line within 5 minutes, didn’t have to do a thing. However, our 2011 iMac (which normally is in sleep mode) must have taken a hit because it won’t power up....Push the button o; the back....nothing. The only thing I tried was to unplug the plug on the back of the iMac and wait 5 minutes, again nothing. The iMac is plugged into a large surge protector (with a bunch of other stuff) surge protector light is on and everything plugged into it is also fine, except the iMac...

appreciate any ideas, thanks, Bill