Overlay Reinstallation of XPP

Long ago and far away in NT4 land, time was that when you had a box go bad, you could simply reinstall NT4 and it would not only fix your problems, but it would leave all your security, program files, settings, ownerships, and the whole shabam untouched so that when you were done with the installation, it was like nothing ever happend to your box. There was no special installation. You just selected the same directory and let it do its thing. Life was great. Then came XPP.

If you try to do an overlay reinstallation in XP, the first thing you find out is that it will delete everything in My Documents (not that I really use that directory). It will also destroy all preferences, settings, ownerships, registry knowledge of installed programs and the whole shabam.

Is there now an installation switch that I am not aware of? My Mom's notebook will not boot, complaining that \System32\config\System is either corrupt or missing. I've had a look, and it is there. I have fixed the HD problem with chkdsk /r. Since it is a notebook, I can take the HD out and put it in one of my external enclosures to try to massage the System file, perhaps find a useable backup. I think there might be a segmented backup I could .reg piece back together (if it worked in a DOS environment or under cmdcons). Ideally, though, would be an overlay reinstallation if I could.

Any other ideas or suggestions? A clean, reinstall is not an option.

Thanks,
Dobermann