Installing for the first time:
FFRend is distributed as a .zip file. Unzip the distribution file, using WinZip or an equivalent program, and then double-click on FFRend.msi to launch the installer. The installer is about as simple as an installer can be: just keep hitting "Next." Note that on the "Select Installation Folder" page, you have the option to install for all users, or only for the current user.
Upgrading a previous installation:
Note that double-clicking FFRend.msi won't work: you will get the message "Another version of this product is already installed".
It is possible to have both versions 1 and 2 installed on the same machine. However, uninstalling either version may cause the other to fail during recording, with the message "Can't create BmpToAvi filter. Class not registered". To fix this, rerun the installer for the remaining version, and select "Repair".