Absolutely.
What you're talking about is a
Worksheet Change "Event".
the subroutine (or macro) runs whenever any cell  is changed.
What you do within the macro  is check to see if the changed
cell is the one you are watching. If so, then you can do
whatever you need to do to open  the file you want.
That is, if you're planning on entering the file name,
then the macro uses the value of the cell to come up with
the name to supply to the workbook.open command.
Or, you can use a "select case" construct to
do something like: if the user enters "1" then open file#1,
if he enters "2", then open file #2, and so on...
so... what is it exactly that you'd LIKE it to do?
(and how much programming knowledge do you have?)