Can some one tell me what is it, well i know what it is but i don't know how to do it, can some one explain it.
overclocking is setting the clock speed of a component over its raed value. it's usually done through adjustments in BIOS, or in the case of Graphics cards, with 3rd party software. if your system was manufactured by and OEM like Dell, HP or emachines there is a very good chance that the BIOS is locked so that Overclocking the processor and ram is impossible.
Can also just put something like defineverclocking in google to get a list of definitions, they may also link to sites with tutorials on how to do it.
Eh, my software for my Graphics card lets me overclock... but, it's true, overclocking on other cards can be done with Third Party software. Overclocking the Processor is just increasing the clock speed over the value that is set at factory.