XBOX 360 Drive Won't Close

All of a sudden, my brand new XBox 360's disc drive won't close. When you press the button, it opens, but when you press it again to close it, it makes a little pathetic noise and doesn't close, but then the screen says it's closed. I didn't do anything that could have caused it. I do have a warranty, but they don't have any in and I'm waiting to return it. In the mean time, does anyone know a way to remedy this?

this could be caused by an object mysteriously be in place of the tray's ejection system. also the following:

a) you have it on a non-level platform, table be not level to ground
b) you have stuck a disc it could not read and it had a read error n tried ramming it in/out

Hmm, it fixed itself...