Being a 2-year vet from the Lord of the Rings: Online side, I know it's only a matter of time before someone asks this, so in the spirit of preemptive anticipation, here's both the problem and the solution:

Q: For some reason, when I exit DDO, it launches my Windows Media Center. Why does it do this, and how can I fix it?

A: Great question! Well, for some reason known only to some past or present dev at Turbine, they include a flag in the program shortcut that is designed (at least for Windows Vista) to invoke WMC once the app terminates. Don't ask me why, but there it is. Now, the solution: Look for the shortcut in your DDO Unlimited folder (likely under Program Files > Turbine) named "mce." This is the offending little rascal that causes this problem. Seeing as I don't like changing original files, right click on this puppy and then do a Send To > Desktop (create shortcut). This will make a copy of the shortcut file on your desktop. Right click on this new copy on your desktop and select Properties. Look under the shortcut tab, in the Target box. You'll see a line of text that probably says something akin to the following:

"C:\Program Files\Turbine\DDO Unlimited\dndlauncher.exe" -mce

Go all the way to the end of this line, and backspace out the -mce (as well as the preceding space) and then click the OK button. Make certain you preserve the quotes at the beginning and end!

There ya go. Problem solved. No more bad ol' Media Center launches.

Just a tip from your ol' Uncle Moncey.