List Box and Check Box

Question

First off, thank you for letting me join VB.Net.  It's been sometime since I program last in it.  Now on to my questions.  I would like to know if Microsoft is going to do something about VB6 running on Vista 64, as my next computer is going to have it.  Don't like it, but what can I do right?  My coding problem is, I have some numbers on the side with a list box on the other side.  The listbox is filled with numbers (some different and same).  If I choose (check) a number on the left side, how can I get the listbox to highlight all the numbers that I check?  Thanks.