Hi,
I guess most of us are also on either Vista or now Windows 7, although I can't say I have ever experienced that problem in whatever op. system or mouse I have used in any version BIAB. Is it a USB mouse? Have you tried it on another Laptop or PC with biab? Maybe it is an actual hardware or port problem.
My microsoft remote mouse only plays up when the battery is low and it sometimes affects the screen until I change the battery.
Sorry not much help.
Jeff