Hello Bill, and welcome to Seven Forums.
It depends on how your Windows 7 was originally installed?
If using a retail installation disc, then you could just do a clean install of Windows 7 to restore it.
If Windows 7 came preinstalled on your computer, then you should create a set of factory recovery discs before upgrading to Windows 8 to have to be able to do a factory restore of Windows 7 if needed in the future. If you like, please post back with what brand and model your computer is, and I'll be happy to find the instructions for how to create a set of recovery discs for your model.