How do i add norton 2010 anti virus i have bought to another pc

If you downloaded the file you will need to find that file and just run the file. If you bought the 3 user license and are trying to install on a different computer you need to log on to your Symantic account and go to your products page and follow the directions to download and install the second copy. If you don't want to go throught eh download process again you can copy the file you originally downloaded to a cd or thumb drive and use that to install on the other computer. You will get the key when you go through the registration process.