No Addon manager either on the task bar above
That's an entirely different issue that, of course, doesn't have anything to do with moving the scenery, repurchasing or activating or reactivating.
As explained, many times already, if the scenery, for any reason, lose its activation, it will NOT DISAPPEAR!!! It will run, perfectly, in full, with every object present, in Trial mode for 5-6 minutes at time.
So, your question is not an activation, reactivation or reinstallation question: it's a problem of why the program is just not working now, which might be related in the way how you "moved" from FSX Standard to FSX Deluxe. How you did that ?
I think you'll have to reinstall also the Service Packs, both 1 and 2 and THEN you have to reinstall the scenery. However, I reallty don't have any idea if this would work, a safer way would be to entirely uninstall FSX Standard, and also remove its folder, then Install FSX Deluxe, Install Sp1, Install Sp2, THEN reinstall all your addons.