GOOD OLD GAME. I love it but there's a huge problem with doors.

You can't open several doors because triggers won't work on modern machines.

I have this game on CD too and I played it a couple of months ago and somehow managed to solve this problem but I can't remember how.

There are 2 ways. The first is by cheating by using NO CLIP-cheat. The disadvantage is, that after usage the game crashes more often and you have to use the cheat several times.

The 2nd I found out was much smarter. I think it had to do with playing in a window or CPU slowing.
I already tried with these programs: CPU killer and dxwnd to no avail. CPU killer is easy to use but can easily crash and dxwnd forces games tu run in a window. It's very powerful and highly adjustable.

Anyone who solved this bad problem, tell it here. If I found the solution (again) I'll of course post it here, too.

Just use the 3DFX version provided by GOG and NOT the Direct 3D version, and these bugs should not occur (according to GOG support).

Already did it. That's NOT the solution (just too easy ;)).

EDIT: I apologize. It IS the solution. I restarted the game and only used the 3dfx version and it WORKED.