I've tried installing the game on two seperate computers, one a laptop and one a PC. Each time, I've used the same save-game. Both computers also have XP as their operating system.
Now then, the game plays fine up until a certain point in chapter 3. I haven't encountered the problem by clicking on Morgan's door, but I have encountered it where you open the box near the patient with that fish and Morgan's office. I open the box and click on the panel to use it, then the mouse cursor disappears and as mentioned, people still wander about and I can use the F keys to make my character say specific things, but it's impossible to progress beyond that point due to not seeing the puzzle interface or being able to move.
Edit: I'll see if I can use a dxdiag for both computers and send my save-game file.
Post edited November 23, 2009 by DavidGil