Speed ups and slowdowns

When playing I-war 2 I get short consecutive pulses of fast and slow game play. Sometimes it goes 2x fast especially when I click instant action.

I also can’t get past the beginning section of the game. When you gets to lucrishas base in the effict it goes black and I have to restart the computer. It’s a good game and I was looking forward to playing it again.

I dunno what’s going on ..it sucks.. A similar thing also happens on Splinter Cell: Double Agent, but thats a different story.

my specs:
XP: home edition SP 2
AMD Athlon 64 X2 Dual Core Processor 4400+
2.31 GHz
2.00 GB RAM
NVIDIA GeForce 8800 GTS

Help meh!