Has anyone had access to your computer recently? Sounds to me like someone's messed around with some of your settings.
Check to see if there's a shortcut with L bound to it. I know you can create a shortcut to lock windows and bind a key to it, [strike]but I'm not sure about the narrator thing.[/strike]
Your best bet would be a system restore, hopefully this would change the settings back.
Edit: for the narrator, hit ctr alt dlt and start task manager. Sort the processes by image name, and look for "Narrator". End this process.