Excel 2007?
Since you don't mention if you've tried tapping [F8], I'm guessing that
doesn't have anything to do with the problem, since it comes and goes and is
screen location dependent.
You might try changing the zoom size up and down and see if that clears it
up when it does happen. A known issue with 2007, fix not released yet.

"Kyle E" wrote:

When I choose a cell to highlight or to begin typing in, 2 or 3 cells below
the selected cell automatically are highlighted. This does not happen on
every excel page or even on an entire page. Usually it is toward the bottle
half of the page.