I don’t follow…
do you mean that you can’t Launch the Editor? you can’t trigger PIE? can’t launch an executable for an Unreal Engine game?
I will continue as though this is “Launch the Editor” for a project you are working on.
is this a specific project, or every project?
where this is a D3D related issue have you changed you Graphic card/driver, your sound card/driver since the last time it functioned (your OS might have done an update a “graciously” changed this during an update).
try opening DXDiag ( you can just go into the start/search bar and type “DXD” and it should be an option but might need the full name if you have never opened it before) and see if you Graphics Card and Audio Divice show up as expected?
is the Engine compiled from source or installed from the Epic Games Launcher?
if from the Launcher does opening UnrealEditor.exe directly work (either through your OS File system, or through the Epic Games Launcher) does that enable you to see your project? can you open the project?
again if installed from the Epic Games Launcher does the Engine version show up in the available list? in the arrow button to the right of the box does “Verify” show up as one of the options?