I've been having trouble with Oblivion lately, whenever I'm done playing and quit, the game doesn't actually stop. Queue the "I can close gates of Oblivion but I can't close the game!" jokes. The game window closes, but Steam still shows me playing and the process is still running according to the task manager. This wouldn't really be a problem if it weren't for a few things: First, I can't kill Oblivion.exe. No matter how many times I choose to end the process it sticks around. Even quitting Steam (through ending the Steam process, as closing it normally tells me to close Oblivion) doesn't do anything. Second, it seems to still be using all the resources it requires to run. As a result, everything is slower and for whatever reason YouTube videos only have audio.
The only solution I've found is restarting my computer, but I'd prefer not do that every time I finish playing. I imagine my nostalgia trip won't last too much longer and it will cease to be an issue, but it would be nice to get this fixed.
I do have a few mods installed, but most of them are unofficial patches and I've seen the game close properly multiple times with them there before so I doubt that's the problem.