It appears that this promo is pre-Vista (and therefore also pre-7). The second step -- "Double-click the "rarreg.key" file, and allow it to write the key data to your registry." -- only works on Windows XP.
For Vista and Windows 7 users, WinRAR will remain in demo/trial mode, with the nag screen.
Most serious video users should probably be using Windows XP anyway, as it continues to remain the strongest OS for a majority of the video tools -- freeware or payware -- currently in use and popular amongst consumers, hobbyists and professionals alike.
If anybody has information on how the key could be installed on a Vista or Win7 system, please post a reply.
Just wanted to note this.
