Well from the "HP Pavillion" I can pretty much garantee you won't get great success with overclocking. Most companies either lock, or severly limit BIOS options (this has to do with the motherboard they use, not every motherboard has the option of overclocking)
I would start by reading up guides on the internet (sorry, none really come to mind right now) about the different terms, and definitions before actually getting into overclocking.
Be sure to get familiar with the terms: BIOS, FSB, mutliplyer, v-core, quad-pumped
Once you feel up the task, enter the BIOS (during startup, before operating system loading screen it will tell you what button to press) Browse around, get as much info as you can in terms of catagories, layout, and options. Post back here with your info

~Bryan~