New
#11
I think I'm probably out of luck. Serves me right for being happy with a 21-year-old keyboard instead of buying a new one every couple of years like Microsoft probably wants me to do.
(For the record, in addition to the MS Natural 4000 keyboard, I also have an MS Sculpt Ergonomic Desktop, which is a wireless keyboard, mouse and number pad set which has laptop-style short travel keys (which I'm sure are still rubber domes) and an F-Lock implemented as a two-position switch, which is, if anything, an even worse implementation than the original's F-Lock key. Oh, and the mouse isn't all that comfortable either. I used it for about a week before I put it back in the box and ignored it.)