Originally Posted by
Moncey
What Vista attempts to do when it encounters a program it knows doesn't like Aero is to automatically switch to a Windows Vista Basic, which is a plain vanilla, ugly powder-blue theme. It puts Aero "on hold" until the offending (or offended) app terminates, at which time it will try to turn Aero back on.
What may happen is when you run DDO, right around the splash screen it may dump back to Windows, trying to "unhook" Aero. I found on my system running DDO a second time (which, yes, means I have to login twice) will usually get me into the game. You can also try switching to Windows Vista Basic (or anything else OTHER than Aero) and see if that works for you.