Why can't you just always start the game as administrator

I think that's pretty obvious. Besides the fact that I don't want to hack in my admin password every time just to play a game (!) the admin account is exactly for that: system administration and not for running ordinary programs.

Hmm, nevermind my post above. Not working anymore, maybe I have to do it everytime I restart the computer or something...

This is getting a bit frustrating.
What kind of magic do you need to get these videos to work?

Manually registering the codec didn't work for me, and neither did: installing the Indeo pack, installing ddfix (via tgfix for Thief 1, via tafferpatcher for Thief 2), using reencoded videos, launching in administrator mode, installing CCCP...

For all those with Win 7 64 bit and no Thief G movies , installing xvid codec (found mine in here : http://www.videohelp.com/download/Xvid-1.3.2-20110601.exe ) solved my problems.
Damn! that game is good :)

I don't know how this works, but I think this solved the problem for me too, where no of the other solutions did do any good...

No luck again.

This has to be the most stubborn compatibility issue I've ever encountered with old games.

Some other things that didn't work: manually registering lgvid.ax, installing k-lite codec or shark007s codec pack (not both at the same time, of course), disabling things like desktop composition, excluding or including the games' respective .exe files from/in ffdshow, enabling/disabling eax via creative alchemy

Thanks Qbex, it worked for me as well!

The main problem I think are the admin permissions in Program Files (x86) dir.
with right click -> run as administrator movies are there.
So i've created a shortcut to thief with "run as administrator" thick in the options.
Everything is ok with videos except the fact that I can't use saved games from my non-Administrator user.

Yes you can!

Go to:
C:\Users\ *YOUR PC USER NAME GOES HERE* \AppData\Local\VirtualStore\Program Files (x86)\GOG.com\Thief Gold

(If you changed your install directory, just try and find a thief folder within VirtualStore's Program files)

AppData is usually hidden, so you may just have to add your username and copy and paste this to your address bar.

Once here, just copy the saves folder into your Thief Gold install folder.

My bad explanation:
When a program doesn't have administrator rights to create or change something in a folder, it will usually do it in the VirtualStore folder instead, when not running Thief as an administrator, or any program for that matter... VirtualStore and your C drive act as one folder in a way.

Installing xvid fixed all my video problems instantly. Windows 7 Pro 64 Bit. Thanks!

Well the videos should still be in the thief game folder, so you can watch them with the media player.

Hmm, I tried downloading the xvid codec, but it did nothing for me. I have the TGFix installed as well, could that be interfering with the codec somehow?
I've also tried all the solutions they've posted on the TTLG forum, noting works.
All that happens when I try playing the intro sequence is that the screen goes black, not even for a second, and then back to the menu.
Running this on windows 7 64bit.

Edit: Stupid me, forgot to run it as Adminstrator. Works perfectly now <3

Thank you so much! I had all but given up trying to get this game's cinematics to play, but this totally works when nothing else did. :D