Toshiba Satellite C660-11M cpu upgrade problem

Hi everyone,
I have the laptop from the title and have decided to try to upgrade the cpu from the stock Pentium P6100 to an i7 640m. I have already bought the 640m off ebay and installed it but it won't boot, just turns on the lcd backlight and spins the fan for approximately 10 seconds and then turns off. I then switched back to the stock pentium cpu and it works fine. I don't understand why this is happening, could it be that I was sold a dead cpu or is it just bios incompatibilty. Both cpu's have the same architecture, family, socket...

 

The notebook may simply not be compatible with the CPU. Intel has been known to use cut-down chipsets for notebooks that use its budget processors like the Pentium line. Even though they're the same socket and use the same technology as the premium Core-series chips, they may not be supported by the chipset.

See if you can find and install the latest BIOS available for your notebook. If it still doesn't boot after that, you can find another notebook that accepts the Core i7-640M and verify that it works in there. Or just sell it on eBay, should be able to get what you paid for it.
I hate to say it, but with a notebook this old, it might just be time to move on.

Charles