Thanks for your advice, I have tried det drivers 41 42 44 45 for NVIDIA and XP the 45 driver seems to be the latest I think, I do have a PCI sound card 5.1 surround sound, there is an onboard AC97 sound thing integrated but I disabled that and use the PCI card (I tried using the AC97 and it still freezes)!
I see it slowing jerking a little when moving the plane around then about a minute later it freezes with stuttering sound, I tried having no sound acceleration and that made it even worse for some reason!
Maybe it has to do with the AVG virus killer installing drivers in some places even although I always disable it before trying to play the game!