Well, I just had a bit of a barney with M$ here. They weren't going to replace it cos I hadn't registered, and didnt have a proof of purchase. I said "Well, in that case I want to register my product now" . Eventually they caved in and let me RMA it.

I have to send it off and wait a week, so I am going to have to buy another mouse in the interim as I only brought one out to Oz with me. Ho well, at least I'll have a spare when it is returned...