FF1 crash

[glsix]

Hi, I've buyed the first freedom force on steam today and have a technical problem I've never experienced with the sequel.

At random, while I'm playing, the screen turn black, sometimes reverting to normal, other times staying black or even crashing the game.
I have an ATI x600 (latest omega drivers). Does someone know from where this problem is coming and if there's a way to solve it ?

Thanks in advance.

PS: after it became worse (complete crash needing a reboot), I find a way to avoid this issue by playing in windowed mode.