dos

My boss has a computer that she runs a DOS program on. How do you change the date on a DOS program? Also on that computer she can’t get windows to run. I have tried to reload windows from DOS but it only goes so far then it gives me errors. Can a person transfer a DOS program onto another hard drive? What I’m thinking is putting in another hard drive then hooking the second one up and transfering the DOS data. Can this be done?