Vista DC problem

Well I just got my new computer (Vista[ewww gross, I know.]). And I tried Zakum, I dc'd right after the first arm died. So someone told me to lwoer my gfx settings so I did and I lasted right till the end of Zak but dc'd upon its death.

As for HT, when I went into the 2nd room I got dc'd very soon after the 2nd head came out.

Specs of my computer:
Windows Vista Home Premium
Processor: AMD Phenom™ 8450 Triple-Core Processor 2.10Ghz
Memory (RAM): 6.00 GB
System type: 64-bit Operating System
NVIDIA GeForce 9100 integrated graphics

It's purely speculation, but most people that I know that DC due to Vista issues all have NVIDIA-video cards. Seems all of the vista users using any other type some how manage to not have issues at the same level as NVIDIA users.

Also, eww integrated

Have you tried switching windowmode->full screen or vice versa in the middle of the fight? That works to fix my lag.