You have WM set up to launch when you press enter. Here's what you do:
You'll need to check all your shortcuts for Windows Media Player. Right click on each shortcut and select properties. Under the shortcut tab, make sure that the shortcut key field is blank. One of your shortcut keys will show 'Enter' in the 'Shortcut key' field. Remove it, and voila...problem solved.
Next step: Call your dad and ask him what he did that for.