That worked, but once if I select another store the button stays disabled
even if that store has no data in these fields.  Is there a way to tell it to
disable only if that particular store had data in it?  

I have all of our stores on one table and it where you select the store
number and fills in the store data on the form.  The date and hours worked
data is manually entered.  There are 12 fields for each Cycle(Month) that has
the date and hours worked.  Most stores will only have 3 or 4 visits per year
so I have a Save button set up when the first entry is made on a store to
append to a table.  If they need to add another visit to this store, I have a
seperate button to edit the existing store that has already be saved in the
table from the first entry.  I want to disable that original Save button if
there is already data in one of these fields so it doesn't get saved twice in
the table.  I am just learning coding so any help that isn't too complicated
is apprectiated.