****AS OF THIS TIME, THESE INSTRUCTIONS ARE OUTDATED. I will be updating them; meantime, find another guide. (There are plenty stickied.)Installing the FreeSpace Open Installer(The official FSOI thread is
here. Author=
Turey. Just so you know...)
Note: This Install process downloads about 3.5 about 8.3 GB of data as of now,
if you download everything. Just so you can prepare; for example, you could set it to download overnight.
OK, First:
Go to
www.fsoinstaller.comClick on "Downloads".
Choose which Installer version to use...

.EXE version: Works with Windows without having to use Java. 20
MB in size. Download it, open it, then skip to the "Using the Installer" section.
--this one is "easy" for Windows users. Not that the .JAR version is hard... but if you've never used the Control Panel before, and don't intend to, then use this option.
.JAR version: Works with Windows, Linux, and Mac. 20
KB in size. Requires Java version 1.5 or higher. See "For Java" section, below.
--this one is cross-platform. It's also exactly the same as the .EXE version, except that it requires JAVA, and possibly using the Command Prompt. Don't worry; I have instructions...
For Java:1st, Check to see if you have Java 1.5 or above.
If you do, then skip to step 2. If you don't have Java, or have an older version than 1.5, or just want to update your Java to the latest version, then un-install the older version(s) (if applicable).
*RESTART COMPUTER*2nd, install JRE 6:
http://www.fsoinstaller.com/getjre.html -Mac users click
here, get the Java for Mac OS X 10.4, Release 5 (Universal). If that doesn't work out, let me know.
3rd, either: (Linux or Mac must use option b, Windows can use either a or b)
a) download & install:
http://www.fsoinstaller.com/files/installer/java/javautilities/javautilities.exe-If you have the Descent: FreeSpace a.k.a. Conflict: FreeSpace, and/or the FreeSpace 2 Retail CDs and you're running Windows, jump down to "Retail install" to save time, then come back and:
download & run (double-click):
http://www.fsoinstaller.com/files/installer/java/FreeSpaceOpenInstaller.jar, then go to the "Using the Installer" section below (underneath the "Retail Install" section).
b) For Linux, Mac, and Windows: (If you have the Descent: FreeSpace a.k.a. Conflict: FreeSpace, and/or the FreeSpace 2 Retail CDs and you're running Windows, jump down to "Retail install" to save time and then come back up and finish:)
open a command window / prompt / console, and type in:
java -jar pathtofile\FreeSpaceOpenInstaller.jar
*Replace "pathtofile" with the actual patch, eg (for Windows, saved to C:\Downloads): java -jar C:\Downloads\FreeSpaceOpenInstaller.jar
-hint: For Windows, the easiest way to get a Command Prompt is Start > Run (Vista and 7 type the word run and it will show up in your results), type "cmd" (for 2K/XP, without the quotes) or "command" (for 9x/ME, without the quotes) and hit the Enter key. To exit a command prompt, after it is finished with your instructions, type "exit" (without quotes) and hit Enter.
EDIT: Windows users: optionally you can download
this .cmd file into the same directory as FreeSpaceOpenInstaller.jar and double-click it.
Now go to the "Using the Installer" section, below.
Retail Install:1. Install FreeSpace 2 from your disks, if you haven't already. Install it to C:\Games\FreeSpace2. Then install
the 1.2 patch.
2. Run the Installer, under the "Installing the FreeSpace Open Installer" section, above.
Using the Installer:1. Press "Next"

2. Press "Next" again, or click the big button to change the location for the FreeSpace 2 install. (Don't, unless you have a reason to, eg, you really want another location or you've already installed Retail FS2 to a different directory than C:\Games\FreeSpace2 .)

3. Make sure "Update Installed Sections Only" and "Say Yes to All" are not checked. Then hit "Next".

4-6. If you are a Windows user, select everything, except for "Macintosh (Universal Binary) Executables", and "Launcher for OS X"
If you are a Mac user, select everything, except for "Windows Executables"
Hit "Next"
7. Wait for the Installer to finish (this may take a long time!). You will know it is done when the "Next" button becomes black, instead of gray.
When it becomes black, click it.

8. READ the NOTES!!! They might contain important information.

After you do, hit "Exit" (The notes are saved in the \FreeSpace2\Installer directory for later viewing.)

9. Hit the Close button on the Command Prompt Window.

10-11. If you don't have it, get OpenAL: (all users, Windows / Mac / Linux)
Go to
www.openal.org, and click on the "Downloads" link on the left.

12. Get the correct version for your OS:
Windows users get "1.1 Installer for Windows" - note: If you're using Windows, and you have nvopenal.dll or ctoal.dll in your Windows\System32 directory, then delete them and then install the newest version of OpenAL. These files are older versions, and will cause problems with the new install.
Mac users get Installer for OS X
Linux users get the Binary RPM, or compile from the source code.

Lastly, if you need help or have problems, post!
PS I do recommend that you play through the FSPort mod first (select "The FreeSpace Main Campaign" in the game's Campaign Room after first selecting the FSPort mod in the Launcher). Then play the FSPort's Silent Threat Campaign (if you want), then play FS2 (select "mediavps" as the mod in the Launcher). Just to avoid plot spoilers caused by playing FS2 first.
For a list of the campaigns' chronological order, see here.My "Features" tab in the Launcher looks like this:
(All enabled, unless specified disabled):
List type:
Graphics:
Enable specular
Enable glowmaps
Enable environment maps
Enable jpg/tga textures
Enable mipmapping
Disable motion debris
Stops fog intersect hull
(not selected - disabled) Disable scale-to-window for movies
Apply Lighting to Missiles (you may or may not want this, check and see if it affects your performance.. turn it on, if you have issues, turn it off.)
HUD:
Another pair of scanning lines
Enable info next to target
Enables 3d radar
Enable Rearm/Repair Completion Timer
Enable the analog ballistic ammo gauge
Gameplay:
Use models for ship selection
Enable 3d warp
Enable flash upon warp
(disable next two, Babylon & Wing Commander...)
Added to "Custom flags":
-ambient_factor 0 -no_emissive_light -fov 0.55 -spec_exp 16.7 -spec_point 0.6 -spec_static 0.9 -spec_tube 1
For tech info, start off by reading
karajorma's FreeSpace FAQ. Then check out the
FSWiki.