I have bought parallels 7 a while ago and upgrade to Maverick os. So I do not have my mac installed with parallels 7. However, I have downloaded trail version of parallels9 and would like to purchase upgrade. How does this work? on the trial version, I just purchase the upgrade key and punch in without parallels 7 being installed? or is there parallels 7 key I need to provide and have it approved so that I can upgrade to parallels 9? What is the mechanism? please let me know