WPHEWWW, let me take this one thing at a time! Overclocking is a trick to make your cpu work faster than it is designed too. For example, if you have a 1.2Ghz processor,  overclocking could get it up to 1.4 Ghz. or better.(assuming your motherboard and/or bios will let you change your clock settings) However, overclocking requires a good working knowledge of front bus speeds, mulitipliers and voltages, and if done incorrectly, can result in a crispy cpu!(learned that one the hard way!) The safest way to improve you machines performance would be to upgrade if you checkbook will allow for it. Also, before you spend money on a new processor, you might first consider a video card upgrade. With so many available on auction sites, (cheap too) you'd probably get a better framerates/dollar ratio that way.