If you installed your game in this order, you shouldn't be having issues:
1. Check system for old SFC3 Cache files/folders that should not be and remove them.
2. Install SFC3 with CD Key. DO NOT install Direct X8 when prompted, GameSpy is optional, but not necessary.
3. Install the All Language Taldren patch
If you have Windows 10, this is where the game can go sideways real quick depending on your system configuration. I have copied this from my SFC3 mod page with regard to Windows 10 set up issues:
Windows 10 compatibility and full screen correction Jan. 2020 Update:
The previous Win 10 fix no longer works with recent Windows 10 updates. Please read and follow instructions noted for Windows 10 compatibility with SFC3.
INSTRUCTIONS:
Install SFC3 onto your system. For the purpose of installing any of a&A Collaborations mods, DO NOT install GameSpy or Direct X8 when prompted. They are not required/necessary for game operation or server access. There is also no need to allow for a desktop shortcut to be created at this point, as a universal launcher is available.
Next, you will want to install the provided Taldren sfc3patch1.01beta2buildv534b patch we offer in all our mods. If no error* message pops up once completed and the patch Word Read Me file loads, install was successful. If not, remove SFC3 from your system and reinstall.
*If you get a quick three line error message that quickly disappears after the patch has installed, this is denoting an incompatibility error associated with Windows 10. It will be rectified with the dgVoodoo + reShade and SFC Launcher offered by the H&S SFC Team.
After successfully installing SFC3 and the Taldren patch, you may encounter a blackout screen and the game running in windowed mode and/or experience a resolution issue followed by an error that reads as follows: "C:\Windows\System32\DriverStore\FileRepository...atiumdag.dll".
This is a causality of running SFC3 on Windows 10. To avoid even having to deal with this frustration after installing SFC3 and the Taldren patch DON'T launch the game just yet. You will need to download and use the dgVoodoo and launcher to fix the issue (links provided). Before opening the dgVoodoo + reShade zip, disable your virus software as it will attempt to isolate and remove the necessary .dll files. This is especially true for Norton users. Open the dgVoodoo + reShade (Jan2020) zip and extract the entire contents to your SFC3 directory. Then download and place the SFC Launcher (August 2019) on your desktop and run the game for the first time through the launcher* (follow the first time using launch guide on the forum page or install instructions here: SFC3 Typhon Pact). The provided HD install package/launcher will auto-detect for future game play without having to manually set each time. If your game plays in windowed mode, simply click Alt+Enter and it will switch to full screen.
*Note: You may need to manually set your resolution to 1024 x 768 and set the game compatibility to Windows XP Service Pack 3 and save the settings. The SFC Launcher should detect and save this when you run the game for the first time.
Note: If your game is not seeing the SFC3 CD in your drive, close out of the game and open your SFC3 directory. Scroll down to a file that says: "sfc.ini". Open the file. scroll down to a command line that says: "MakeItSo=0". Change it to: "MakeItSo=1". The game will now play without the SFC3 CD. Note, this will be automatically done for all our mod installs.
At this time, you should be able to play the stock Mission & Singleplayer campaigns in full screen. Because of Windows administrator settings, you will need to give yourself rights to modify this directory and sub-directories (important if you installed in the Program Files(x86)). Once done, make a copy of your stock SFC3 directory and archive it as a backup. Example: "SFC3 Stock". You will be editing the other SFC3 Directory folder from this point on for a&A Collaborations mods or any mod you choose to work on/play.
Please note, some older AMD graphic cards and system setups may have a problem rendering SFC3 visuals correctly regardless of the dgVoodoo fix for Windows 10.