If you installed the Windows 10 Technical Preview (like I did), you might want to roll back to Windows 7. As will all preview builds, there isn’t an easy way to do that. Microsoft has stepped up and provided a mechanism to rollback your Win10 TP install to a regular Win7 install.
The Software Recovery website allows you to create a new installer for DVD or USB. All you need is a valid key. You do have a valid key. Right?
If you want to take a look at the bigger picture, this same website would work if you lost your media and need to do a repave or feature upgrade. You don’t have to use it only for O/S roll-backs.
Below is a link to the site. When i tried it a few minutes ago, the site was barfing. If nothing else, it proves there is a page for the site. 😉