basically ive finally got my computer just as i want it . all the right programs on it etc etc . now how do i make a back up of the whole computer ? is this possible ?

its cos ive finally got the right music players , audio programs and conversion progs etc as for my luck with computers , they usually last 6 months then break etc and i lose loads of stuff including important programs . then i cant remember what i had or where i got it . like certain progs that ive paid for and then ive forgot i had it then i cant download it agian , if you see what i mean .

do i basically need to copy each section to disk or a spare hard drive ? can i copy the entire desktops bits to another hard drive ? if i can i will just buy an external one , they seem cheap enough now days ?

really would like to know how to do this cos i do love my computer at the mo