Desktop icons and multiple monitor configuration

I have a user that is having trouble with his desktop icons. He is using a Dell laptop. There is a second monitor plugged into the VGA connection and a third one plugged into the PCMCIA card slot. The third one utilizes a Village Tronic card. The user has an intermittent problem where the desktop icons on the laptop’s monitor will move around by themselves…more or less to a left-justified position. This will happen whether he is hooked up to the other monitors or not. I have no idea if there is a way to lock the desktop icons so this does not keep happening. I’d appreciate any help I can get. Thank you.