opening form(s) from listbox double Click

Ok I have ran into a problem that I need help with. I have searched but cant find anything that I need.
Ok my problem is. I have a 2 forms. form1 is full screen and I have a list box and command button. when i click the command button I have it to ask 2 questions and put the answers as the caption on form2 and also into the listbox when I click the command button again (on form1) it asks the questions and opens another blank instance of form2. All this I have working fine so far my problem lies with when I double click the listbox on the form1 I want it to make form2 with the right caption on it to the front (make it Visible). I can't figure it out or find it anywhere. Any help would be great

thanks in advance
james