I really got hooked on mods with xbox and skyrim. I bought a pc so I could get deep into mods. Recently been playing skyrim and have mods threw nmm and haven't had "too" much trouble. Just a couple days ago I downloaded Oblivian and went to the scan part on nexus to get set up. Oblivian never showed up and now when I try to get into my nmm manager a grey box pops up and says skyrim is not set up to work on nexus and if you have game installed, to rescan. On the top of the box it says unreco
First thing I would do is reinstall Nexus.
Second: Sometimes you get overwrites of the .ini files in the documents folder on the C: drive. Just delete the .ini files and try the game, if it starts, it will rebuild the .ini files.
I am guessing that you do not have your games on Steam. If you do, you can run a file integrity check.
Reinstall Nexus. It may act as a fresh install. You may have to reinstall all your mods. You may have to reinstall the Skyrim game. Same goes for Oblivi