finding my product key

[smithyboy43]

i picked my computer up from The Windows store at the mall today, there were a bunch of corrupt files so they reinstalled windows, i was told i would be able to just log into my account on office.com and download it...problem is it shows no purchased products....im wondering if maybe i bought it from somewhere else, like the little box with the disk or whatever and didnt use an account?
I need office every day for school so i cant be without it for long