If you know how to use Windows Explorer you can highlight Program Files (x86), then press the new folder button and give it whatever name you like. Then when you get to that window where they ask where to install just press the browse button and locate the new folder and you are good to go.
As for finishing off a 6.2 document in 7.1, I did it without any concern at all. Save as the 6.2 document with a different name, then open the new named document in 7.1. If it fails you can always go back to the original and try again.
As an author you probably ought to be doing a lot of saving as so you not lose your work no matter what happens, including deciding the murgatroid should not really marry whosit after all!