Hi Sunset. II'm Greg, awarded MVP for eleven years, Volunteer Moderator, and Independent Advisor here to help you until this is resolved.
1) Try replacing the HDMI cable since it seems to be involved.
2) Other fixes for the known issue of screen flickering:
http://windows.microsoft.com/en-in/windows-10/t...
https://www.windowscentral.com/how-fix-screen-f...
https://windowsreport.com/fix-laptop-screen-fli... (Avoid ad links which intrude into editorial copy, especially avoid Restoro ad)
https://avita.zendesk.com/hc/en-us/articles/360...
https://www.youtube.com/watch?v=5Vl3EmyZX2s
3) The Display driver is so important here that merely updating it is sometimes not enough. So let's try everything possible to get it working correctly:
First make sure you have updated the Display driver from the PC or Display adapter maker's Support Downloads web page for your exact model number, HP Serial Number or Dell Service Tag - from the sticker on the PC.
If necessary first remove the old driver using DDU (not necessary with Microsoft Basic driver which is a placeholder if nothing else is available) and/or installing in Safe Mode with Networking (so you have internet), or Safe Mode, accessed by one of these methods:
https://www.digitalcitizen.life/4-ways-boot-saf...
While there check also for newer chipset, BIOS/UEFI firmware (very important), network, sound, USB3 and other drivers, comparing to the ones presently installed in Device Manager reached by right clicking the Start Menu.
If this doesn't give you the latest or ideal driver for what you need, compare it to the driver offered by the Intel driver update Utility here:
http://www.intel.com/content/www/us/en/support/...
or the Nvidia Update utility here:
http://www.nvidia.com/Download/Scan.aspx?lang=e...
or the AMD autodect utility here:
http://support.amd.com/us/gpudownload/windows/P...
For Display issues one fix that is working is to Roll back or Uninstall the Driver on the Display Device > Driver tab, restart PC to reinstall driver.
You can also try older drivers in Device Manager > Display device > Driver tab > Update Driver > Browse > Let Me Pick.
Then you will know you've tried everything in addition to Windows Update drivers.
Adjust the screen resolution until it fits and looks best at Settings > System > Display.
4) Go over this checklist to make sure the install is set up correctly, optimized for best performance, and any needed repairs get done:
http://answers.microsoft.com/en-us/windows/wiki...
Start with Step 4 to turn off Startup freeloaders which can conflict and cause issues, then Step 7 to check for infection the most thorough way, then step 10 to check for damaged System Files, and also Step 17 to test a new Local Admin account. Then if necessary continue with the other steps to go over your install most thoroughly.
5) If nothing else works then do a Repair Install, by installing Media Creation Tool, open tool and choose to Upgrade Now. This reinstalls Windows while keeping files, programs and most settings in place, is the most stable method to advance to the latest version, and solves most problems.
http://windows.microsoft.com/en-us/windows-10/m...
I hope this helps. Based on what you report back I can answer any questions and may have other steps to perform.
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