2010 reinstall

I am having trouble re-installing VRD 2010. I installed it on 2 other computers and it worked fine. Now when I install it on my newer PC and another one it refused to take any license. Where is the license file located for 2010? Is it in the appdata roaming? Or do I need to import the registry license? I can't find any good info. Also... If it was purchased for 2010 will 2010 R2 work with the license? It seems to work on one computer but not on others.... Any help? Thanks!