Hi. I'm having a guest guru-type engineer come over to my studio to help me sort out some tough mixes. I use an unusual track ball mouse - Mouse Traks Professional - which is a hell of a mouse once you get used to it, but takes a while to get used to. I'm sure my friend has a mouse he prefers and would be a lot quicker using. Can we use both mice at once? Or can XP only load drivers for one mouse at a time? My mouse is a USB mouse, I'm not sure what my friend would use. . .