I am trying to upload some presets for lr 5 and I can't without the license key. Before when you bought tangible product this key would be on the back. However since I got it from the cloud, i don't know where to find it. Any help
You mean, LR is asking for it's own licence # when you try to upload some presets?
It sounds strange to me...
Open LR, then from the software preferences, go to the "Presets" tab and click on the "Show Lightroom Presets folder...".
Copy and paste your preset there and restart LR... it should be do it.