Command + w stopped working

Hi,
I use a 2009 Macbook Pro, which is very well loved and well taken care of. Recently I was goofing around with Quicksilver configuring keyboard shortcuts for iTunes, and I added one which was totally unrelated to the preset shortcuts. Once I did, though, Command + w stopped closing tabs. All the other shortcuts work, my keyboard is set to the usual language (it's an azerty keyboard), I've restarted several times, and I even restored all shortcuts to default. Command + t, q, a, all work. And obviously my w key works as well. It just seems that that shortcut is bugging.

Any advice as to what I could do to fix it? I don't honestly know all that much about computers, but with instructions I could probably try something.

Thanks for your hep,

Virginia

Does Command-w work properly when booted to your recovery system media? How about if you create a test user account? Is the symptom tied to the system or the user settings?

Alright well I made a new user account, and it seems to be working, so I'm guessing it's tied to my user settings somewhere. Still haven't been able to find where, though.