I've just gotten this game:
Sherlock Holmes: The Case of The Vanishing Thief
The problem is it won't play on Vista due to the Macromedia Projector error.
(Think it's a quicktime thing)
I've searched high and low and found no solutions. Not even any of the compatibility settings work.
It's said to be working on XP, but I highly doubt it.
Too bad, since it's a great little game, so it would be nice if GOG maybe could make it work and add it to their collection ;-)

Yeah, games relying on old versions of Quicktime (before 3 I think, when the player got that metal look) and Macromedia (now Adobe) Director (which I think Projector is a subset of, possibly a player component) are tough to handle. Newer Quicktimes have a different API than the first few versions, and I'm inclined to think Director isn't being actively developed any more (its functionality being incorporated into Flash instead, though not in a backwards-compatible way).
The way to handle those would either be to rework the game and convert the media to newer formats (yeah right, good luck with ancient Director stuff without access to the original source files), or try to find some alternative implementation of them.

We've had this issue (among others) at work with old software. Three different things you can try, but they are not that recommended. Sometimes these work, sometimes they don't.
1) Mess around with compatibility, try *every* combination. By every, I also mean: If the game is NT/98, try running as XP etc...
2) Turn down Hardware Acceleration. Remember to turn it back to normal after gaming.
3) See if the CD/DVD has a copy of quicktime/macromedia on it and install. This potentially causes other issues with XP/Vista (you have two different versions running/installed at once), but it adds the files it wants.
-
A second solution is to run XP or 98 as a virtual machine within Vista. Or, use a second PC.
What you really want is for the game to be updated for modern systems, chances = low.

Its an outside chance but you could try Quicktime Alternative. Its a codec pack of sorts that enables playback of QT videos without the player and I've not had any trouble playing old MOVs with it.
PROBABLY won't work but its worth a shot

This, I believe, would be the most compatible way, seeing how the requirements for most games relying on Director or Quicktime are quite low by any standards., there should be no noticable slowdowns in gameplay.
If I'm not remembering very wrongly (haven't used QTA for long since I'm one of the few who actually like QuickTime), it doesn't provide any of QuickTime's APIs, just support to play QT files through the Windows Media APIs (that is, Windows Media Player and other programs that uses Windows' codec system).

Right, I was afraid it was one of those games, that needs Virtual machine to run.
Haven't really had any need for it yet, so I think for now, I'll leave it on my shelf til I get enough time to fire up my XP machine again.
But thanks for all your suggestions :)

Well, I never got it to work on Vista, but it plays beatifully on XP with no problems at all :)