I have a HP computer that is 5yrs old I like to take both hard drive from old computer and put them in a new bare bone system but old copy of windows will not work in new computer.

More info, how are you moving drives to new PC? What steps are you taking?
What connections have you made? Does the light come on when you power on PC? Does the cd rom light come on? Does anything appear on the monitor?
Just try to give as much info as poss. The more info will help as far as steps you've done and things you see when trying these things