This is a solution I found for my computer about missing GfxUIEx.exe for Intel HD Graphics Control Panel.
Recently I bought a new Dell computer with Windows 10 and updated my Intel graphics driver. But after updating when I try to open control panel from start menu, a dialogue box showed up saying GfxUIEx.exe is missing. GfxUIEx.exe is usually located in the 'C:\Windows\system32\' folder. I kept the dialogue box open and the computer automatically detected the folder it was located. If anybody have the same problem try this location, it might work for you.