Insert a row at a specific cell value

I was wondering if anyone knows how to program the following macro.

I need a macro to insert an entire row when it finds a specified value in a column. To make matters more complicated it needs to copy the format from the above line onto the new line and the column will have blank cells. For example:

The Data may be:
I specify that I want to insert a line when it finds "gg"

aa
bb
cc


dd
ee
ff
gg


So the result would be:

aa
bb
cc

dd
ee
ff

gg



Thanks and feel free to ask me more questions if you are vague on anything

Hey Paul, Thanks for your help. How do I set it to look for a cell value. In the example I gave you I used "gg" however I want this to be dynamic so it could be any value I specify, not just gg.

Paul..thank you so much this really helps. Do you know if there is any way to copy the formulas and formats from the above row onto the newly inserted row?