Hi Jay - as stated above. Drag the 2nd spreadsheet in and select 'add data' and it will load in both.
The trick is that there is a field with the same name in BOTH spreadsheets.
If there isn't a commonly named field but there is field that means the same thing (like employee ID vs employee number) you can rename it in your underlying spreadsheet (you will have to start over) so that the name is the same and start over.
or you can go into the load editor, and put in an alias using the 'as' word to rename the fields in qlikview only.