Does this laptop have an nVidia graphics chip (GPU)?
If so, you may be experiencing the same problem I'm having with my DV6000 series laptop.
You can read my thread on the Linux board HERE
I suspect I am going to have to get the GPU chip "re-flowed" which is basically repairing the flawed solder joints securing the GPU to the motherboard.
If you are familiar with any Linux operating systems, (Ubuntu, Mint, Puppy, etc.) you could do as I have and create a bootable CD, DVD or flash drive to operate your laptop. For some reason, Ubuntu (v11.04) will run my laptop flawlessly, but Windows locks up. I still haven't quite figured it out yet, but I think it has something to do with how the graphics are rendered. WHS has been a great help and as I stated in my thread about my issue, I'll post when I get it all figured out.
These HP laptops apparently did not have the best design when it came to heat management for the CPUs and GPUs and this causes a poor connection between the motherboard and the graphics processor. When the GPU loses connectivity, you cannot interface with the PC, so the only thing you can do is a hard shutdown. As we all know, this is bad when the PC is processing something and can cause file corruption leading to other problems.
Hope this helps.