Steam Launching Problems

[DaysBefore]

Since the Steam Client update a few days back I've been unable to play Medieval II or any mod for the game. Stainless Steel, for example, previously started without going through the Medieval II launcher, now it starts the launcher, but I am still unable to start the mod. Instead it opens a second launcher window, after which it says "App already running" and closes. I have the same problem with Broken Crescent, Last Kingdom, any of the Kingdoms campaigns, and now the base game itself. I've tried moving the entire Steam directory outside of Program Files and into Documents, as I've seen suggested. It allowed to launch Broken Crescent once before returning to it's previous problems.

Does anyone have any help to offer? I'd very much appreciate it.

[irishron]

Have you asked the respective mod forums?