Sooooo... are the other two cores unlocking or not? The first post says no, but now you say yes. I am a bit confused.
My wife's computer is running an Athlon II x3 that unlocked the fourth core and now shows up as a Phenom II x4 B35, but not in every program. BIOS sees it like this, as does Belarc Advisor, but not some others. Is this what you are talking about?
If it won't boot when you unlock the cores then it is not stable. Unstable means unusable unfortunately.