Many of your issues are mentioned here in this FAQ under the Thief 3 section. If you are using an AMD dual core that could be the repeating intro movies problem. The solution is to set your system to only use 1 core...a pain I know. I have an Intel so didn't get this one on my dual core. Look here for that issue and more.
http://www.ttlg.com/forums/showthrea...9ba686&t=75031
I am glad you are playing this game cuz it's a great game really. I have been playing it on and off for a year but recently set it up on my new system and it looks great. Many don't like it because it doesn't feel as much like Thief 1 and 2 out of the box but there is a large mod (well a series of 4 mods) you can download that tweaks alot of stuff in the game and gives more of a Thief 1/2 feel to the game. It adds alot of high-res textures too for those of us who want the immersive experience and it changes many things for the good. I highly recommend it but of course, sort your technical problems out first with the game. The mod is here and I installed everything in it and didn't look back. Just download all of them.
http://www.john-p.com/textures/Thief-DS/index.shtml
Pity they ditched Garret's cape though....Let me know how it goes eh? Perhaps disabling one core will fix everything as they all seem kind of similiar (hangs, repeats etc.).