According to HP's specifications, your laptop has the Intel Core 2 Duo P7350 CPU and nVidia GeForce 9600M GT GPU.
There are some desktop motherboards that support mobile CPUs and SO-DIMMs (such as the Jetway NF93R-LF or the IBASE MI945P), but they're all in the mini-ITX form factor meant for small home servers, HTPCs and other such applications. Considering that the P7350 CPU is several generations old now, it might be more economical to get a modern motherboard with a 2nd or 3rd generation Core i3 and DDR3 RAM, which will likely have similar power consumption but far superior performance.
But if you're on a budget or don't have very high requirements, then both of the boards linked above seem to be good choices for re-using your CPU and RAM.
The GPU is where it gets really tricky. The vast majority of laptops have the graphics card soldered on the motherboard (even if it's a discrete part with its own video RAM). In the rare cases that the graphics card is removable, it uses the proprietary MXM standard (of which there are several revisions, to complicate matters further), and you'd need an MXM-to-PCIe adapter, which don't seem to exist.
Other components you might be able to use from your laptop include the hard drive (using a 2.5-to-3.5" mounting adapter), the WLAN card (using a mini-PCIe-to-PCIe adapter card) and the display panel (using an LVDS controller board + power supply).