I have the same 27xw monitor, and it flashes on and off occasionally. I am running 1920x1080 resolution with an HDMI cable.
HOWEVER, I do not believe the display is defective. It only does it on webpages that have videos on them, like facebook. It's almost if the monitor is switching modes or something. It doesn't do it any other time unless there is a video on the page.
On the other hand, YouTube does not cause this flashing of the display.
I wish I could resolve it but honestly it doesn't happen all that often. It doesn't do it when browsing the web or playing games, so as I said, I do not believe the monitor or the power supply are to blame.
Does anyone else notice this? Trying to find a pattern here...
Thank you for showing your interest in HP Support Forums. It is a great place to find the help you need, from other users, HP experts, and other support personnel. I see from the post that you are having an issue with the monitor screen flashing on and off. Don't worry as I have a few suggestions which should help you to resolve this concern,
To provide you with an accurate solution, I'll need a few more details:
When was the last time it worked (date)?
Have you made any software or hardware changes on the PC before the issue started?
Was there any update/reset interrupted recently?
Have you tried with a different HDMI cable?
Are you using any adapter to connect?
In the meantime, let's try these steps here:
Let's try with a different HDMI cable.
If the issue persists, I would suggest the next step would be to perform a factory reset on the Monitor. Please refer to this guide for factory reset.
Please respond to this post with the result of your troubleshooting. I look forward to hearing from you.
If you wish to help others looking for the same solution as you've found, mark the post as Accepted Solution.
If you wish to show appreciation for my effort, please click the Thumbs up icon at the bottom of my comment.
Thanks for pulling out the "form" but I'm a little more advanced than that. Not going to follow your steps, sorry. The community can try to sort it out without the pre written garbage from "customer service."