I would look at doing a clean install of Windows. It basically just puts Windows 10 on the computer and removes all the crap Dell added on. I always find this to provide a nice boost. If something screws up or you want to go back and use the old Dell software, you can use their recovery partition. In any case, if you go the clean install route, this should help guide you (there's also a ton of YouTube videos).
Start fresh with a clean installation of Windows 10
It does seem to be common for what it's worth (with Civ 5 at least). Just a quick Google search shows tons of threads about it. But man the fixes seem like a pain in the ass.