At the second level I have really slow glitchy gameplay making it unplayable. It is fine up until then. You have just killed the turrets on the tank and you drop down and try and open a gate and it says you need to find a hacker. Its when you go under the tunnel and a enemy carrier pops up and as soon as the soldiers start popping out it goes very glitchy and stops and starts. I have a P4 3.GHZ, 1024mb RAM, Gigabyte 6600GT, Audigy 4 Sound Blaster sound card and Windows XP Professional.
I can attach or paste a dxdiag if necessary.
Have got latest drivers and also tried down grading the drivers on the graphics card to no help.
Any ideas gratefully received?