I know I should learn more about it but is it possible for me to overclock to only 2.8ghz from 2.4ghz without changing other things since its such a minimal amount? Even 2.6ghz would do for me.
that little won't make a bit of difference.
SR-71 brought up a good point, if that is a prebuilt computer, it will most likely have a locked BIOS making overclocking impossible. there may be software to "cheat" with but that is NOT a good idea.
when it comes down to it, yes you need to know and understand what you're doing even for a 2% OC. thats like wanting to drive a car "only" around the block w/o learning how to drive a car.