You need to make a system repair disk if you don't have the original Windows disk.
My method.
I only image drive c, which is exclusively windows and programs. I have relocated all file locations, Doc's, music, pic's, etc, to a separate physical hdd (e). I manualy backup data to a third hdd (f), which also has the image file (of drive c) on it. This drive is removed from the pc when not in use.
When I fitted a new (faster) hdd, I booted from my windows disk. Then selected repair. It found the image on my third hdd. I then took the tick out of the box, so as I did not format drive e with my data/files on it. It then partitioned my new, larger, drive to the size of my old hdd and, minutes later all was working. All my files were located correctly on drive e. Just as before.
I do it this way, because I personally don't like to use backup programs for files, as I don't want to be tied to a program in order to get them back.
I've always said. Use the method you prefer, so long as you do make backups.