Before I ask the question, I am aware that I could fry my mobo/cpu if i overclock too much, its a crappy pc, so i'll take that risk.

I have a compaq Model S4010CL computer
And I believe the mobo is locked.
Is there anyway I can unlock the CPU or mobo to make it any faster, even if a low amount?

'Locked' or 'unlocked' is usually in reference to the CPU multiplier. Intel CPUs can not be unlocked. However, you may be referring to the FSB. If it's not adjustable in the BIOS, you can try overclocking software.

How can I change it in the bios.

And if that doesn't work, what is the best o/c'ing software i can use?

Since you have a Compaq I doubt you will be able to overclock through the bios. You could do what jam suggested and use overclocking software within windows, but there is ussualy poor motherboard support. Since you will have a proprietry board made for Compaq it is even more unlikely you will be able to overclock. Unfortunately most brand name PC's like Dell, Hp and Compaq are pains to upgrade or overclock in any way.

Mattwizz3 : )

Sempron 2600+ @ 2.2GHz
1Gb DDR400
Asus A7N8X-E Deluxe
200GB SATA / 80Gb IDE
256Mb MSI 6800 Ultra

Well, I got it overclocked from 2.39 GHz to 2.52 GHz without being unstable. I overclocked it to 2.6-7 GHz and then my sound wouldnt work for some reason, I just heard some strange clicking noise in my speakers. I turned it down to 2.7 and the sound on wmp still studdered. I guess
2.52 GHz is as high as I can get it.

Overclocking a Celeron will just make it suck even faster. :P

Anyway, your sound isn't working because as you nudge up the FSB, you also nudge up the AGP and PCI bus. Your sound card, whether integrated or discrete, runs off the PCI bus. Find an option in your overclocking software that locks the PCI bus. You'll then be able to overclock a lot more that way, if your RAM can handle it. I doubt overclocking software provides RAM dividers, though.

Overclocking a Compaq? You didn't do any research on this at all, did you?