I need to know how to find the first "empty" caption property of several labels.

Here's the scenario:
I have two different types of products, therefore I made two seperate forms to identify all the products needed (put on frm2 & frm3) > frm4 compiles the products onto one form I would like to find the first "empty" row to insert the product > Any suggestions / methodologies?

Flint

People think we make $3 million and $4 million a year. They don't realize that most of us only make $500,000.
Pete Incaviglia, baseball player, 1990