This looks like something a lot of people would find helpful. My luck, Doc has already posted this.
Win7's no-reformat, nondestructive reinstall
By Fred Langa
Microsoft won't tell you this, but you can do a fast, nondestructive, in-place, total reinstall of Windows 7 without damaging your user accounts, data, installed programs, or system drivers.
That means you may never have to do a full, from-scratch reinstall again, even when your system is misbehaving so badly that a full reformat-and-reinstall seems the only answer!
As I'm sure you know all too well, from-scratch reinstalls are ordeals. They take hours. And when a reinstall is done, you still have to recreate all your settings, reinstall all your software, and so on. It can take days to fully recover from a total reformat/reinstall.
Windows' little known, in-place reinstall takes only a fraction of that time and effort and yet completely rebuilds, repairs, and refreshes an existing Windows installation. It leaves your other software alone (no reinstallation needed!) while also leaving user accounts, names, and passwords untouched.
When you're finished, your Windows installation is just as it was before, except that all the system files are fully repaired, refreshed, and ready to go.
This nondestructive-reinstall ability has been in Windows since XP. (See this XP reinstall article that I wrote for another publication, years ago, when XP was new.) But — for reasons unknown — Microsoft has never made nondestructive reinstalls an official repair. In fact, it's not even listed in Win7's System Recovery Options (Help & How-to page).
(Vista users, you're not forgotten! The nondestructive reinstall process for Vista is nearly identical to that described in the rest of this article.)
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