We have a computer that came pre-installed with Windows 7; we didn't receive an installation disk for that. How would one create a setup installer disk from a machine which has Windows 7?
The built-in backup utility system image option with the following system repair prompt will basically give you a setup disc with the current configuration.
Also, using imaging services like WDS will easily pull a valid image from the computer. Using a Technet subscription all installation images can be downloaded or you can copy someone else's installation media as most Windows 7 setup discs are generic these days and usually include all SKUs.
Generally as an end-user, you want to uninstall the bloatware and then go the system backup route for this, according to anime-paul anyway ^^