Q: Power button is not working?

aussi3itup,

That user option has been removed from the Energy Save preference.

OS X Mavericks: Using the power button explains how it is supposed to work.

aussi3itup,

I also use (command+option+⏏) to put my iMac to sleep.

What computer are you using?

Have you experimented with varying the pressure/time of depressing the button?

Mine works as stated in the article.

I am not positive but placing your On OFF button isn't ment to be the primary way to let your computer go to sleep. But, rather when you are finished using your computer walk away from it and it will go to sleep on it's own.  Then when you want to restart the computer simply single click your Mouse or trackPad and it will wake up.  Go to your Black Apple if you want to shut your computer down or turn it OFF.

Cheers

Don

aussi3itup,

You may be interested in exploring this article, by Topher Kessler Disable new power button sleep mode in OS X Mavericks | MacIssues.

The method has changed in 10.9.2 since many with laptops couldn't manage to not hit the power button when reaching for the delete key. You have to hold it momentarily to have it sleep. If you hold it for a little longer, you will get the shutdown dialog. If you hold it for about 8 to 10 seconds, it will force shut down.