windows 7

i have  a windows 7 computer . i wanted to make a back up HDD  . i tried to clone it first but it would not boot . then i tried a system image  and system repair disc . it never worked. then i tried system recovery discs [5 discs] it didnt work either . i tried it  on 2 HDD and not one of them worked . i have never had so much than this windows 7 . does any one know how to make a back up HDD  for windows 7 ?, i have tried every thing .