Starfox: I've decided to make a step by step guide of what you need to do in order to get Thief Gold running perfectly (that will apply to Thief 2 as well, should GOG release it). Those instructions specifically target Windows Vista and Seven but work for XP as well.

Download and install the game

That's quite the obvious part. What is NOT obvious is where you should install it. Thief Gold (Thief 2 and System Shock 2 as well) should NEVER -- and I stress NEVER -- be installed in the program files directory or you may run into troubles later especially if you want to run some FM (Fan Missions). So install it anywhere that is NOT into the program files directory. That applies to a lot of old games anyway, not especially the Thief series. Personally for everything coming from GOG I created a special GOG folder on one of my drive. Feel free to name it anyway you want.

Download, install and configure ddfix (version 1.5.12)

You can get the latest version of ddfix directly from there: [url=http://jermi.dyndns.org/~jermi/ddfix/ddfix_1.5.12.zip]http://jermi.dyndns.org/~jermi/ddfix/ddfix_1.5.12.zip[/url]

Once downloaded, open the zip file and extract everything in there to the folder where you installed Thief. Now download a free hexadecimal editor if you don't already have one (like HHD Hex Editor Neo for example but feel free to choose the editor you like).

Open in the hex editor the file Thief.exe found in the folder where you installed Thief (for Thief 2 it would be Thief2.exe and schock2.exe for System Shock 2). Using the find feature of your editor, perform an ASCII search for "ddraw.dll" (no quotes). You should find two occurrences of it close one to the other. Edit ddraw.dll so it reads ddfix.dll instead for both occurrences. That will allow Thief to use the ddfix library instead of the ddraw one. Save the file.

Test your installation

At this point it's always a good idea to test your installation to check if you did it right so launch the game and try the training mission. Everything should go smoothly and the video should play nice and clean. By default ddfix comes with safe parameters enabled so you shouldn't have to worry about changing them right now.

Configure your screen resolution

Open the file CAM.CFG located in the Thief install folder an look for the line:

game_screen_size

Change the two values behind this line to meet your screen native size (or any size you want). For example my screen native size is 1920x1080 so I changed this line to:

game_screen_size 1920 1080

Save the file. Start the game. It should display perfectly in your resolution (save for the menus that are always displayed with a 4:3 ratio); in game you should have a widescreen 16:9 or 16:10 depending on the resolution you entered (that is if your screen is widescreen).

If everything looks and run good at this point, you probably don't need to mess with the ddfix.ini file (which contain the parameters you may modify to adjust ddfix way of doing things). You may try to change them but backup a ddfix.ini that works before fiddling around so you can just restore it if something goes wrong.

Note that when you use ddfix version 1.5.12 you don't need any other widescreen tweak or patch. It's already included.

That's it, you're done

Well there is always the issue of EAX when using Creative sound cards. Try out this post for that:

http://www.gog.com/en/forum/thief/creative_xfi_sound_card_owners_here_is_the_fix_for_eax_sound_positioning_and_movie_audio

Of course for more help you can go to TTLG.com (which are quite the old timers when it comes to everything Thief)

Starfox: I What is NOT obvious is where you should install it. Thief Gold (Thief 2 and System Shock 2 as well) should NEVER -- and I stress NEVER -- be installed in the program files directory or you may run into troubles later especially if you want to run some FM (Fan Missions). So install it anywhere that is NOT into the program files directory. That applies to a lot of old games anyway, not especially the Thief series.

sk3mo: Sadly this didn't fix my problem.

sk3mo: Sadly this didn't fix my problem. I'm running a Core 2 Duo, GeForce 8600m GT, Vista laptop and alas - it still fails to load past the select difficulty screen.