Okay, I’d like you to try removing configs for editor for us. Go to \Engine\ folder ( C:\Program Files\Unreal Engine\4.7\Engine by default) and copy Config folder to desktop, then delete original from Engine folder. Then try opening editor through Launcher.
If editor launches without issue, please and attach that entire folder ( ones saved to desktop) to this post so we can take a look at what might have caused problem. Thanks!