“Sorry, you can’t install the update because it isn’t supported by your computer’s CPU.”
I don’t understand what could have changed in Windows 8.1 that makes it no longer able to run on my computer.
Edit: My colleague has highlighted that it will be lack of CMPXCHG16b support on the Intel Pentium 4 630 (Prescott 2M) 3.00GHz CPU in the computer. Windows 8.0 did not require this instruction. Windows 8.1 requires it.