Late last night I was almost finished setting up my computer after wiping out the hard drive and re-installing everything from scratch. I downloaded the full version of Nikon Capture 4.2.1 and when I went to register it using the installation code I have since I purchased the product I got a message saying that the program expects numbers in the fields (the old installation code consisted of letters). It appears that Nikon changed the installation code scheme, fortunately for me I had an old copy of 4.0 saved and all the upgrades leading up to 4.2.1. This meant that I had to spend extra time installing partial upgrades and re-booting the computer. Now I have to chase after Nikon to get a fresh installation code which may prove hard to do because I have no idea where the original invoice is, I hope they accept my installation code as proof. If you are using Capture 4.0, I would suggest to either contact Nikon for a fresh installation code, or make sure you keep the old files around in case your computer crashes.