what matters?

well as i have said i have a budgie named budie and i have him with me right this second as i write this and he as become quite attached to me and he happens to love fighting with me the only problem is he is older now and can bite very hard. this is not much of a problem if i like playing it to but he think that when i’m doing my home work on the PC [for people how don’t know what a PC is well hate to tell you but your using one now] it’s time to play so he jumps from my shoulder to the desk to the keyboard and every time my hands get close to it he runs over to bite me really hard. how do i train him not to do this?