Grey shading to row when checkbox unchecked

Hi,

I'm creating a cost calculator sheet with a list of items that can be checked or unchecked. I am very new to VBA and am wondering how I get a row to shade grey or be "ghosted" when the checkbox for that row is unchecked. I want the background colour of the row to be light green when checked then grey when unchecked.
I know it can be done as I have a copy of a calculator done by someone else and this is what happens on theirs but its locked with a password so I can't see how they have done it.

I have attached a copy of my file (COPY Preliminary Cost Calculator). I have also attached the copy file (Copy of final_quotationcalculatorv2only21092009)I have which shows what I'm trying to achieve with the grey shading.

Thanks in advance