Two questions I'm sure have obvious answers

Till I build my custom rig next year, I have a pre-built HP PC that's I've upgraded extensively. it handles all the current games without any problems at High settings. My question is the following, HP has a lock on the BIOS so I cannot OC my CPU. Is there a way to bypass the lock? Or are there alternate methods to OCing a CPU?

correct me if im wrong but can rivatuner OC ur cpu?

i had the same prob on when i had a Dell XPS and i also think the only way you can do it is by calling the company for the code, but i doubt that will happen : /