Transfering Data from Several Sheets to another
 

I have a workbook with 31 sheets in it. I want to create a macro that will
grab all the data from A25 - A43 on every sheet and transfer that information
to a single column on a sheet called "Upgrades". I want to make sure that I
don't over write any of the data.

Also, not every cell in that range will have information in it, some will
blank.

Thanks!