You've mentioned two different products, Intel GPA and the Graphics Checker, and it's unclear whether you're talking about installation issues with Intel GPA or the Graphics Checker, or both.
So can you please go into the Windows "Programs and Features" control panel, remove both Intel GPA and Graphics Checker, then reboot. Then first reinstall Intel GPA and copy any installer screenshots that show any errors.
If your installation is ok, then try getting the latest version of the Graphics Checker, then install that and again copy screenshots that show any installation errors.
Hope this helps and that you're quickly back and running with the new version.