donna,
I'd say your most immediate source of help will either be the place that
sold you the computer, or more likely, the computer maker's Tech Support.
Since you just bought it, someone at one of those places should be able to
assist you. If you got it at some place (should I mention BB?) and you let
their pre-delivery bunch do setup on it, they may have done some strange
setup that is preventing the trial from operating properly.
Again - which version of Excel/Office did they give you as a trial?
When you try to type into a cell, what happens? Just simply nothing, as it
totally ignores you, or do you get any type of alert, warning or error
message? If you do, what does it say?