I have a secondhand one-button Apple Bluetooth mouse that I've been using with my MBP. Worked well enough up until this evening. I just put in a fresh set of batteries, but now when I turn it on it kills the red laser output as soon as it SHOULD start using it. That is, when I first power up the mouse, the laser starts doing it's "flashing detect" thing, just like normal. After a few seconds the computer sees it and connects... but when it does that the mouse turns the laser off. It remains paired--the computer can see it and reads the battery level fine, and it even registers clicks in the OS. But since the laser turns off, it won't detect tracking at all. In fact, I even know the optical sensor is working, because if I turn it over the pointer starts drifting because of the lights on the ceiling, apparently. The laser ain't broke, since it turns on initially, the batteries are fine, the connection is fine, and I tried re-pairing without luck. Anybody seen something like this? Any suggestions other than "chuck it"?