MousePad Gone Wild With Arduino Uno

Hey!

Whenever my powered Arduino Uno board is within a foot or so of my Sony laptop, the mouse touchpad freaks out and quickly becomes unusable! Connecting the Uno board to the USB port makes the mouse go even crazier. I've used this PC with other development systems (e.g., Parallax) without issues. I'll try powering it from a 9V battery next. Any other ideas?

Thanks.

Equipment:
Arduino Uno board
9V power supply, 9V ± 0.5V, 650mA ± 30mA (suspect?)
SONY VAIO VPCEB33FX (using USB 2.0 port)

Does it happen more from one side of the laptop than any other? Or is it the same no matter where the Uno is as long as it's within a foot?