I, too, have had this problem with Excel. On my home computer, restarting
Excel has thus far done the trick; however, on my work computer, I tried this
several times and it didn't work. In this thread, I saw that someone simply
changed the zoom to 100% and that took care of the problem, so I tried that
and it worked for me. It's annoying that I can't zoom out like I would like
to, but at least I can select one cell at a time.

"Elaine" wrote:

Having the same issue. Just posted in the more recent item titled "Excel
keeps selecting two cells". I have a Microsoft Intellimouse Optical USB... I
doubt this has anything to do with the mouse.

Closing and reopening the document does not help. Restarting excel does not
help.