How to make OSX the default boot partition?

[jeffreytb]

I installed windows on my imac and later deleted the partition. But now when i boot it says something like no bootable devices in like this black screen. I know to hold the option key to select OSX but i need to know how to make it boot automatically. Any help?

 

[toolbox]

When your booted into os x, go into system preferences find start up disk then click on the Macintosh HD icon ( it will tell you what OS is on the drive ) then click restart. That will set the boot order.

Or do a PRAM reset that will also clear it and default the OS X partition to be the start up one.