I downloaded Lightroom onto my desk top, but the computer is just too slow. I want to dis-install it & put it onto my laptop... How can I do that without buying a new licence??
Just do it. I don't know what version of Lightroom you are using. But regardless of version, you are entitled to two installations for your personal use. If you have a standalone version, then you will need the serial number that you used before. If you are using the creative cloud you won't need a serial number. But all you have to do is use your standard uninstall process to remove Lightroom from the old computer and then install it on your laptop. If you have done some work in Lightroom that you want to keep, then these instructions will help: http://www.lightroomqueen.com/how-move-lightroom-to-new-computer/