Corel changed my monitor display settings, how do I restore it to default?

 My boss tells me this is an old bug and in older versions you could change it back in the Colour Management diagram. So where in the new Colour Management dialogue can I change it back? The screen has gone downright fluorescent- not just in corel, but over the whole desktop. I've tried colour calibrating the monitor but even with the brightness and contrast down low, all the colours are obnoxiously bright.

I have no idea how it happened, I just turned on the computer one day and had to shield my eyes. Any help would be greatly appreciated as I'm not well versed in profiles and such yet, and all I need is a quick hand to restore the default settings.