It all stated by me getting annoyed with F1 key. As it is only a registry change, I did it manually; easy enough.
But then I got another laptop that had no context key (damn you HP). So I remapped Right Alt to Context menu. But I also wanted F1. And for my media computer with a strange small keyboard, I wanted to do other mappings too. Quite soon it was obvious that I might as well create application instead of calculating mappings by hand.
This application gives you ability to remap any hardware key to another using the Scancode Map registry value. Once configuration is written (and computer rebooted), application doesn't need to be running for mapping to work.
Additionally, if you want to use manual mapping, it is useful to get scancode information for a key and there is standalone Scancode Viewer included too.