SOLUTION second CPU core not detected Windows 7 / Vista(?) 0xc0000225 64-bit (no HAL)

Originally posted by me on the mass effect 2 forums

(scroll down for the - possible - solution)

So i have the same problem as everyone: dual core CPU, but only one core was being detected, causing the game to malfunction.

I came from windows xp sp3 ultimate, and i decided to get windows 7 as a solution (seeing my friend had win7 and his game runs flawlessly). However, i installed the 32-bit version (don't know 100% sure if that matters) and still only one core was detected. But it seems like there's no Detect HAL option in win7 either!
I googled a bit and it seems like many people using win7/vista are experiencing this problem.

I thought that maybe installing the 64-bit version might work.
But dear lord, fate strikes again: after the 64-bit install goes all the way to 100%, my PC reboots but gives an error trying to boot win7:
"Unexpected error blah blah blah some-error-page ... ERROR: 0xc0000225"

So i googled for that error and again, many people using win7/vista are expeeriencing this problem, mostly after a fresh 64-bit install.
Then i encountered a topic about some guy saying that the technicians from the shop told him that his memory timing was bad, and he had to set it manually to 1333MHz

So what i did to get win7 64-bit to work:

Get into BIOS and look for your Memory Frequency, set the mode to MANUAL and then select the highest frequency (probably 800 or 1033 or 1333).
[I ALSO DID THIS: go to power interface in BIOS and ENABLE APIC, however i think the real problem was caused by the memory frequency] [Note: enabling APIC may cause linux operating systems to fail. Just disable it again to use them] Make sure you SAVE before exiting BIOS.

Can anyone confirm this works?

NOTE: haven't tested wether ME2 actually runs perfectly, but i am 100% sure that my 2 cores were now detected.

UPDATE: scratch the NOTE at the end. ME2 works perfectly

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