Is it a computer you built or did you buy it at something like BestBuy? Most computers bought at a store come with basic motherboards and bios that don't allow any modification of clock speeds. Also, do you really need an overclock on that computer? Overclocking can be useful is certain situations, but it's not going to magically make any computer faster. Overclocking can also generate a good amount of heat compared to the stock clock speed, so you have to be certain that your CPU cooler and system's airflow in general is capable of handling more heat that it already is.
In any case, as k1114 already stated, you don't have an unlocked CPU, so you won't be getting much out of it, even if you can modify the options.