Mac wired keyboard not working with imac

Mac wired keyboard not working with new iMac.
Well that's not exactly true, it works through a 4 port USB hub. This is a new style Apple Keyboard with Numeric Keypad - English (USA). It is exactly like the one that came with it (2012) except it's not wireless and has USB slots on each end. I need the number keys and USB ports. $49.00 at the apple store. This problem seemed to start after the power went out. Keyboard would not work on iMac. Moved wired keyboard to Mac mini, worked fine. I unplugged all USB items, shut down computer and unplugged power plug for 15 seconds. Sometimes I may have held in the power button when unplugged for several seconds. These things worked a few more times and then that stopped working eventually. Later I tried Resetting the Parameter RAM. That did not solve the problem.
Strangely enough I have my old PC keyboard and that always works with my iMac.
The wired mac keyboard always works with my Mac mini. It just will not work reliably with my iMac, new in 2012 running Snow leopard. Can't Apple make a keyboard that works with their computers? I am using the wired keyboard now through a simple unpowered 4 port hub but I can't use the USB ports in the keyboard. Very frustrating.
Larry

Try resetting the System Management Controller on your iMac. Do this: Remove the iMac from the AC main power (shut it down first) by removing the plug from the outlet. Let it set that way for 15 minutes. Plug it back in and restart. If the keyboard still refuses to work correctly, exchange it for another with Apple. All Apple accessories are warranted for 90 days.

I tried that and unfortunately it didn't work.
It's out of warranty but I wouldn't get another because this one works perfectly on my Mac mini and a new one might not work either on the iMac.
I guess I will have to buy an off brand keyboard if I want it to work with my iMac.
Thanks for the reply anyway.
Larry

Well after trying a few more things I tried the Resetting the Parameter RAM procedure again. This time it worked. I was using a PC keyboard to do the procedure previously and maybe I wasn't holding down the right keys. Instead of command+option+P+R, I used Ctrl & Alt + R&P keys.
I'm putting this here in case it might help someone else with the same problem.
Thanks, Larry Luvin my Mac again!