Delete a shortcut key??

I recently purchased a Surface Pro 7 and have an old Dell. The Dell had a 'problem' in Excel that whenever I hit the "/" key it would initiate a shortcut, I think, where the "/" was not entered and the screen took on this appearance----

Note the MANY black boxes in the area at the top of the screen filled with digits and letters!!! I lived with it as I figured that I must have inadvertently created some kind of shortcut. Wondered if it would happen on my new computer. Now on my new Surface of which I signed up to the Microsoft One and am using a cloud version of Excel, the same thing happens when I strike the "/" key???? Does it in transferred documents and in new ones I've created quite simply to see if it occurred in newly created docs. Can I get my front slash back?? What do I need to do?? Am 70 years young and would like some assistance in trying to recover the '/' .......... tired of copying and pasting!!!