Hmmm....lemme see if I have another mouse that's in working order around here.
BTW, it's a serial mouse. I's on thelaptop and I've got a real keyboard plugged into the PS2 mouse port.
Ah...laptop. Well...that complicates things a bit, doesn't it? Does it have a trackpoint or stick of any kind? Sometimes those get wonky...might be worth disabling the stick if it does have one. Some of 'em only let you do that in CMOS, I think.
Meant to say...on mine, I can disable the stick through Windows - I just go to the Control Panel and to Mouse, and there's a Device Settings tab that lets me disable the touchpad or pointing stick or both. That's more common than not, but if yours is older...