It's rather simple. Loop from A1 downwards until you find a cell with that particular value. Then go down one more line and unhide it (or possibly: select line and line below it and unhide).
I won't provide code, but it's not especially difficult.
The best thing to do: buy an introductory book on VBA programming in Excel.
Or: Find VBA code and examples on the net (easy to find with google, search for Excel VBA unhide row for example) and study the VBA Help that comes with Excel.
I always advice the first to start with and only turn to the Internet once you've mastered the basics of VBA programming, but you might prefer the other way.
I want to create a macro in excel which when assigned to a button, will unhide a row. The row which needs to be unhidden will change depending if the row above it has a value in the first cell of that row. If that is the case, I need the macro to unhide the next row. Does anyone know how to do that?