[CentOS] hp laptop

I have a new hp laptop, I installed centos 5.5 on x86_64.
I was only seeing one core in /proc/cpuinfo.
The CPU is core i5 M450 which should be dual core.
So I put a more recent kernel on the machine, 2.6.34.7
did the compile and all - rebooted and I still only see one core in 
/proc/cpuinfo.

the i5 M450 is a dual core cpu. Is there something else I am missing?

Thanks,

Jerry