Here is a Vanilla Kernel 10.6.7 with Lapic.c fixed (also knows as xnu-1504.9.37) that has lapic issue fixed (that affect HP's laptops).

Installing or replacing the kernel will give you the option of booting up 64 bit mode and no more using "cpus=1" to boot up.

Note: The mach kernel must be replace after installing 10.6.7

Vanilla Kernel 10.6.7

Enjoy it..