one of my computers is a bit old now, about 6 years, and the hard drive is starting to make them clickity click click noises

so, do i simply go out and get a new computer?

or do i get the hard drive changed?

and if i do, how do i get the stuff on the hard drive copied over totaly so that i can simply swap them over?

is there software available or do i hand it over to a nerd in a shop to do?

thanks