You don't. Most of the internals are accessed by removing the keyboard as the system board lies beneath this. Generally speaking with laptops, you remove screws from the underside to release the keyboard which lifts out from the top, allowing you access to most components.
Please see the HP Maintenance and Service Guide which is freely available for all HP & Compaq laptops and details procedures for removing and replacing most (if not all) parts. The guide for the NC6120 can be found here: http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00502970/c00502970.pdf
Hope this helps.
Valiante, May 2007
