It is impossible to do a repair install with any version of windows other than windows XP. actually it is sort of possible but you need the exact version of windows that was originally installed which makes it impossible. You also need to revert all changes to the OS that were made from then to now such as the service packs and specific updates. So even though it is sort of possible under some rare circumstances it would be a kind of silly to try as its to much work at the end of the day.
You should know as well there is only that OEM versions are actually retail. There are only two official versions of consumer level windows 7 in north america which are Windows 7 RTM x86 and Windows 7 RTM x64. Both include all versions of windows 7 basic, home, pro, ultimate. You can manipulate the installer is various ways to install any version you please or simply recreate an all-in-one disk. (they did this as XP was a mess with all the different types and versions)*You can in-fact legally download from microsoft distribution source; which is digital river; any version of windows or office available to avoid infection via torrentsalthough these links are not officially listed by Microsoft people have taking note of the link locations and compiled lists of the download links and personally I use this site here:
All Official Windows 7 download sources
All Official Windows Vista download sources
All Official Microsoft Office 2010 download sources
All Official Microsoft Office 2007 download sources
As I explained in the first paragraph it being impossible I should mention how simple it is to reinstall and restore to its previous state because all the relevant information that makes their computer unique in located in their user profile. Its all pretty simple as all you need to do is make a backup from a second computer and make sure you get the user profile contents, APPDATA folder contents, and PROGRAM DATA folder contents then but re install windows with your RTM disk. Once install update drivers and update windows all the way. now copy over user file contents and program data contents. look through the appdata folder and copy everything that is not on the new installation and additionally look in the [appdata\local\microsoft] and [appdata\roaming\microsoft] folders for anything pertaining to the mail provider they used and copy their contents for all their email messages and account settings. At this point after all the content is back in place just go back to the [appdata\local\microsoft] folder to see what programs they had installed so that you can re install them. Once their programs are re installed all the settings they had will be there as if they never lost them including favorites, and contacts, ect...