I had the same issue and what I did was uninstall Skyrim, right clicked its grayed out name, went to properties, Local Files, Browse local files and then I deleted everything that was in that file. I proceeded to delete everything Skyrim related (that was left behind after the uninstall) on my hard drive as well as the Nexus mod manager. (I made a backup of all the mods I downloaded in .Rar format) I then re-installed the vanilla game again and it now runs like it was just this moment bought. This is just merely one way to fix the issue at hand. It's the most direct way to solve the issue and I hope that you're as successful as I was. -Sketch-
