Error when trying to install Windows 8.1 "CompareExchange128"

[FFX]

This is driving me nuts, every time I try to install the update I get this error. I ran CoreInfo to see if my CPU supports PAE, NX and SSE2, as these are the requirement for Windows 8.1, and everything is supported! How can I fix this?
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[FFX]

Anyone else who has encountered this problem? Information for fixing this, is really scarce. And over at answers.microsoft.com they haven't answered yet.

 

[anayajenny]

You didn't get the answer yet. Is it still giving the same problem?

 

[jnjroach]

Is there an updated BIOS or Firmware for the machine? It looks like if 8.1 can properly read the CPU you can load the 32bit version or attempt a CPU Check By-pass....

[Q] Win 8, bypass PAE/NX/SSE2 check - Page 12