Stop playing runescape, if your older than 12 your too old for it.
Kerbaos, this was possible on runescape in 2001, approx, in 2009 its impossible, since 2002/3 there were no hacks, just bots, except the ocassional glitch somewhere, all calcs etc are done by the server, Cheat engine can change the amount of gold it looks like you have, but its only client side.