Mass Effect Unable to register or download

Hi,

So i recently built a new gaming pc and have just downloaded origin and tried to insatll the mass effect trilogy i bought awhile ago through EB Games/Gamestop. I installed and registered all three games on my laptop originally, but now I dont have that computer anymore and wish to play them on my Desktop. When trying to install any of the Mass Effect games from disc it doesnt let me continue unless I enter my activation code. Unfortunately I don't have the piece of paper with the codes anymore. When looking at my origin account I can see that I have the three games there but when I left click on them a box pops up saying "An error ocurred". I am also unable to right click or view any other information about the game in order to view my product/activation key. Also this is a brand new computer so I have never had mass effect or any games through origin installed on here and am therefore unable to find the keys in backup folders etc.
Please help, I really do not want to have to buy another copy.