Mike before installing VSD version 7 make a back up of your project,
And remove V6 completely as having both on one machine causes chaos
when you open a project from V6 in V7 it will make a few changes all of its own, a known and intentional change in the V7 which was an important and usefull edit from the way V6 worked.
I would also advise you do a save as and re name your project (ie) VSD V7 2013 project name, and work with the newly save version so you have the original to compare to.
Good luck, V7 is a lot better than 6 was