Upgrade Parallels 6 to 7

I have Parallels 6 running with Mac Lion on a 2010 Macbook. I have purchased Parallels Desktop 7 and I want to use this to upgrade Parallels 6 to 7.
1. Can I just insert the disk and upgrade Parallels 6 to 7 without corrupting Windows 7 and the programs and data running on Windows 7?
2. Will I have a problem in the future when I upgrade from Lion to Mountain Lion?
3. At the end of the year, I am planning to get an iMAC. Will I be able to transfer Parallels 7 to the iMAC? Will I need to buy a new copy of the program to run on both computers?

Thank you.

Robert R. Michiel, M.D.