For some reason (a reason I am seeking to discover) the mice I've used on my Titanium PowerBook do not necessarily register upon plugging it into the USB port. The infrared eye of a black Apple mouse and an IBM mouse will blink a couple of times then turn off. Unplugging and retrying up to a dozen times...it finally works. Other mice like one Logitech will point, but won't click! I have a wireless Logitech that has always worked, no issues...and the white apple mice I use off design lab computers work fine. any ideas what the deal is? enlighten me. much thanks.