I found that, with Quicktime 4, I can get the videos to run on Windows 8 regardless of what compatibility settings I use with one exception and that is putting the game into 16bit colour mode, which, it turns out, seems to be the only thing I can do to get the frame rate running properly. With compatibility for XP SP3 and 640x480 resolution, plus the QT fix, I can get vids and a slightly jerky (but not as bad as it can be) frame rate, however as soon as I put it into 16bit colour mode, I lose the videos... (and get a beautiful frame rate). It's very frustrating.
EDIT: Scratch that. The frame rate is only 'slightly jerky' on the menu screen. In game it's still better than it can be, but it's also hard to live with.
EDIT2: Clean install, applied unofficial patch, XP SP3 compatibility, 640x480 resolution - still the same problem, either videos and awful frame rate, or 16bit colour, no videos and beautiful frame rate... grr!
EDIT 3: Tried using XP SP2: no difference. Tried using the edits to the .ini file which the unofficial patch allows, with CpuIdle = 1: no difference. I am completely running out of ideas now. I've been trying to get this game to run properly (on and off) for nearly a year now. I just don't know what to do.