OS X became unresponsive

[winty03]

Last night I was listening to some music via iTunes on my MBP. I had only iTunes running, it was plugged in charging a low battery and had head phones plugged in. That was the setup. This happened to me 3 times in a row and the only thing I could do was push and hold the power button and restart it. What it did was once it was going to the screen saver and the screen flickered between the desktop and the screensaver, it was like it didn't know which one to do. The other 2 times I was using it so that never happened. But the reason I had to do a hard reset was the mouse was un-clickable. I mean I could move it but when I would attempt to click it would not select the object it was on. I also noticed the entire time it was like I had did a right click on the desktop because it was constantly pulling the "select" grouping window all over the desktop. (The way you select more than one object on the desktop.) After the 4th time all was fine used it for maybe another 5 mins and turned it off. Any ideas what it could have been?