I bought a computer which had been booting up on 3 cores and not 4. I have tried to boot up with all 4 cores but the computer will not start further than the "starting windows 7" screen. The seller has said that it has previously run with the 4 cores. I have a geforce gtx 240, a 500w PSU 4gbs of ram. Any ideas how to fix.
More about :quad core boot problem amd phenom 2ghz
Sounds like you got ripped off. B55 usually designates a Phenom II X2 that someone attempted to unlock the other 2 cores on and obviously failed which is why it was sold as a dual core processor to begin with.