I have the original FSX loaded onto my machine, but I was thinking about getting the Deluxe version for the added missions and features. Will it install just the necesary files to upgrade it to Deluxe or do I have to delete the original version and then install Deluxe. I really do not want to use up all the Hard Drive space with two versions...
you should uninstall the standard version. All your rewards, etc., will not be deleted.
You can then sell the standard version on eBay for a few bucks.