Hi lelask,
Since you upgraded to Deluxe from LR Basic with Sem 1+2 content, you don't need to reinstall LR or import your key again.
Kindly check if your LR is not on "trial mode" or if you can play your course lessons without being asked for your key -- if so then you don't need to import your key.
Just in case anyone else encounters this Deluxe upgrade problem, the only time when you will need to import your key is when you upgrade from LR Basic Sem 1 to Deluxe (because in this case your key will be replaced with one that unlocks both semesters).