If you would post the Product number of your Omen, It helps us better.
Its usually written on the bottom of the case somewhere.
I was just curious in what way the built in monitor wasn't working. For example, is it just a black screen always or does it look like fracture lines across the screen?
As for the external monitor, sounds like its showing the boot logo but when Windows fully boots, Windows want to show on the internal screen.
You didn't mention what you've tried so far so here are a couple of things that might work.
There should be an F key with a monitor logo that will switch the Windows screen to the external. Usually on an Omen it the FN key in combination with F4 (Unless its F5, F8, etc. depending on your specific keyboard layout).
Or try pressing the power button to start it and close the lid. Some systems will automatically switch to the external then.
I have asked the customer service and got the reply is, wait for their call, I need to send back to them I think, I use all the methods he told but nothing changed. I think may be my gpu has been broken by sudden electric shock
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