Vista - KB953026 does not apply to this system?!

Hello people,

Having some problems with running GTA IV, and i think the problem is caused by VISTA, not the game itself.
After many hard restarts due to system freezes i debugged the memory.dmp file which windows creates when it's not shut down properly, and although i don't quite understand the "symbols" needed for correct debugging, i think it's pointing out to a faulty file, namely> Dxgkrnl.sys.

Know i've done some research and found out that YES, this file when not patched can cause a system crash/freeze, so i downloaded the fix for vista x64 KB953026> Download details: Update for Windows Vista for x64-based Systems (KB953026)
But everytime i try to install it, a popup comes up saying that it does not apply to my system! but it has never been installed in the past, it's not in the update history, so why won't it install?? any clues on how to fix this? or make it install?

I've once read somewhere that stuborn installations like this can be dealt with manually, through extracting the .msu file, yielding the cab file out of it, and slipping that cab file in some windows folder :3eyes: but i really can't find the exact way on how to do this...

Hope i'll find some help, will be very thankfull.