How to go back from windows 8 to IOS on Mac

[DubaiBreeze]

Hi,
I bought windows 8 and the activation key has been sent to me. I wanted to install windows 8 on my Mac, so I started with bootcamping everything was ok till the end after it rebooted it asked me to put the activation key but unfortunately the activation key is not correct
As its asking with 5 digit Numbers between the dashes but the one it's been sent to me is 6digit numbers between the dashes
So, anyway... I decided not to continue so I had to cancel everything
But now after I rebooted my Mac it looks like I will have to install windows 8 because it tells:
"No bootable device-- insert boot disk and press any key"

The question is how to get my Mac operating system back?

 

[simsaladimbamba]

iOS is the Operating System for the iPhone, iPod touch and iPad (mini), Mac OS X or now OS X is the operating system for Macs.

To boot back into Mac OS X, press the OPTION/Alt key right after the startup chime sounds and then select the Macintosh HD to boot from.
Once booted into Mac OS X, go to System Preferences > Startup Disk and select the Macintosh HD as startup disk.

To learn more about Mac OS X: Helpful Information for Any Mac User by GGJstudios​