Hello. I occasionally get into a situation where whenever I move the mouse
it highlights cells and I can't do anything else. Pressing escape or a mouse
button (or pressing any other key it seems) does not stop this effect and I
am forced to do a ctrl-alt-del and end the Excel task so I can load Excel
again to get it back to normal (losing all changes etc). Last time it
happened I was trying to do alt-t,p to protect the sheet when it began.

Thanks in advance for any advice you can offer.