Remove grass under building

[Remove grass under building]

None of these works for me, the Helipad is still visible.

[FPS isn't everything...]

Well it's not easy to enjoy a game at 10 FPS

[Will my PC Run this? What CPU/GPU to get? What settings? System Specifications.]

I'm running it on low now and got FPS between 15 and 25, but I got one problem. small white dots starts appering in the trees while i'm playing, I just wondered if anyone knows how to fix it?

[Will my PC Run this? What CPU/GPU to get? What settings? System Specifications.]

Can anyone tell me if my computer will be able to run ArmA II so it's atleast playable.

This is what I got

GPU: NVIDIA Geforce 7900 GTX

CPU: AMD Athlon 64 X2 5000+ 2,6Ghz

MEM: 2 GB

OS: Windows 7 Ultimate