Installing FreeSpace 2
From FreeSpace Wiki
There are several methods to installing FreeSpace 2. The supported methods include installing from the boxed media, manually setting up the retail data, or installing using the GOG distribution.
Installing from CDs/DVD
This is the default way for Windows users. Perform a normal install of FS2 if you are in Windows, or if you want to use this method in Linux or OS X, you should be able to run the installer via Wine. That exercise is beyond the scope of this article however. Once the game is installed, it leaves the movies on the installation media. You will want to copy the .mve files from the CDs/DVD to the data/movies folder inside your FS2 dir, for example C:\Games\Freespace2\data\movies\, creating the data and/or movies folders if they don't exist. If it's not already, you will want to patch the game to version 1.2 (GOTY editions already are). Now you will want to proceed with Installing FreeSpace 2 Open
Installing with only the game data files
For this method, you will need a collection of .vp files. These include:
Create a Freespace2 folder and put these .vp files in it. Generally these are the only .vp files that should be in your folder, save for a few exceptions. These all need to be v1.2 files. You can safely put the multiplayer misison pack and multiplayer voice pack in with these, and if you don't have the .mve cutscenes, you can put the FS2OggCutscenePack.vp file in this directory as well. Any other .vp files should typically be installed as a mod, by creating a folder in the Freespace2 folder and putting it in there. Multiple mods can be used through mod.ini files, so there's not usually a need to stick a new experimental .vp file (or other game data files) inside an already working mod folder.
You may also want to get the HUD color presets.
Installing from Good Old Games (GOG.com)
The GOG version is a single Inno Setup Installer executable file, just run it to install the game. Be sure not to install to a path with spaces in the name. At first, the GOG version installed one .vp file that was not updated to version 1.2. This should have been fixed in newer versions though.
Installing from the .cab files on Linux/OS X
If you have access to the installer files from retail media, but you can't run the installer, Linux and OS X have access to a little tool called Unshield (OS X version is in Darwin/MacPorts). It can be used to extract the retail data from the cab files. Then proceed with the Installing with only game data files instructions.
GOG Install Methods for Linux/OS X
If you have the GOG version and are on *nix, the install method can currently be a little rocky. You will either need Wine, or a Windows install more than likely. Either one should work with both options you have. Essentially you can either install the game, or unpack the installer. Installing should be rather straightforward, in Wine this will be a task for the reader to enjoy. Once installed you can either use the directory you installed it to or copy the .vp files listed above to the final location. Extracting the installer requires the use of the Inno Setup Unpacker command line program, which should be very easy to use even in Wine. Download the innounp program, and use the -x command line option to extract the required files listed above. Then follow the instructions for installing with only the game data files.