Yes, it's called disk imaging, and you do it with programs like CloneZilla, Ghost, or TruImage.
Once you have a computer set up the way you want, it lets you take a snapshot of the way the computer is at that particular instant, and then later you can restore the computer back to that specific instant.
Other options are programs like Deep Freeze or Microsoft SteadyState. These programs essentially allow you to prevent any changes being made to the computer. Essentially every time you reboot, they are restored back to a specific configuration.
I have 40 units of computers use Windows 7, but often get the virus, so having to reinstall that take a long time. Is there an easier and shorter to copy windows 7 into a computer without having to re-install? like to copy only the harddisk computer? Please help, thank you very much.