Suddenly external monitor not working with Windows!

Nov 18, 2006
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Anytown, USA
Your Mac's Specs
27" iMac 2.7GHz Core i5, iPhone 6, iPad Air 2, 4th gen Apple TV
I pretty much only use the Windows on my Mac for gaming, so the external monitor is an important part of that. It's been working fine for a couple months, but today for some reason it's not working any more.

It actually does work fine through the boot up process. Then after the desktop is loaded up the screen blipps out for a second and the external monitor picture doesn't come back the the MBP LCD picture.

Anyone have a clue why this is happening??

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