Excel is not the only app that does this and I have tried it on WinXP home
and pro with similar results. Maybe someone here has the answer. Turn on
Caps Lock and type uBR(space) using the Shift key to produce the lower case
u. As soon as you hit the Space Bar the text reverses case to Ubr. Any
takers on this? In my job there is a piece of equipment called a uBR and I
was trying to type an all caps header in Excel 2000 that said uBR PORTS.
After several attempts and a re-boot, I watched the text carefully after
each keystroke and that is what I found.

Mike F