Registration Code

I bought the Sims 3 in December of last year. I had to buy a new PC laptop due to problems with my old one so now I want to play the Sims 3 again but I have to install it into my new laptop. However, when installing it, it says that the registration code has already been used. 

I thought it may work if I logged into my Origin account but I cannot remember my login information.

Please help!