I was just wondering what a repair install does to the registry. As far as I can tell, it does nothing so if you have some corruption in it a repair install won't fix it.
Any input appreciated but please don't state something as fact unless you know for sure and can demonstrate it. Thanks
I don't know the answer for WinXP.
FWIW, the last time I did a repair install it was on Windows 7 ( see here
), it has been years since I did this on a Windows XP computer and I know it wasn't as controlled as that Windows 7 occasion. I mean, I don't have any snapshots of an XP repair before and after to examine what was really done by the process. In that Win7 case I did grab filelists and registries but even they are not perfect because I was rushed. Anyway, let me start by explaining one thing - the only way to say with certainty what was actually done is to get copies of the registry, registry exports, and filelists, but done from outside the operating system. Either pop out the HDD and drop it in another computer setup for this kind of thing and collect the registries and a thorough filelist, or alternatively, if you have access to ERD/DaRT you can boot it up and do the same plus a complete registry export from its registry editor, dumping to a flashdrive. The reason I am explaining this is because filelists and registry exports done on a live system are limited, not everything shows up. Comparisons using them will be totally inconclusive.
Now I can say that the Win7 repair process is a really impressive thing they pull off with multiple reboots and replaced in-use files and such. It preserves installed programs and "settings", this means that non-Windows files are not tampered with, and most importantly the registry with its myriad intertwined keys and data are carried forward - but - additionally, Windows is reinstalled as well. ( Again, I cannot answer about WinXP here ). When I did some diffing ( NOTE: this was a bear of a task, huge registries, needed bigtime CPU overclocking and other prep, Windiff froze, ExamDiff finally worked ) I learned that large swathes of the original registry were copied verbatim, perhaps the whole thing at once, and then machine settings were punched in and/or completely replaced which "fixed" so-called registry corruption. However, "corruption" means different things depending on whose asking. Real registry corruption, like a broken database from file defects like missing delimitters causing a key to run into another should be fixed because when the original file is read-in and written-out they presumably use error checking to toss any bogus keys or data. Corruption can also simply mean changed values in machine keys like device driver settings that leaves hardware not working properly. These would also be fixed in the Win7 process by the ( presumably ) 2nd step that reinstalls Windows. So I would say IMHO, that in Win7 at least that the "registry corruption" is in fact corrected as well as it can be. User programs that were buggy before will still be buggy though, that is by design because no user items are tampered with.
My suggestion is this. You have an WinXP installation with a possibly corrupt registry? Get another equivalent HDD and clone this WinXP system drive from outside the operating system using HDD tools like Seagate DiskWizard. Now you have a nearly identical copy to work with, use this new HDD for experiments. Do what I said above, either pop the clone into another reliable computer and grab the filelists and registry hives or boot ERD/DaRT and get them that way. The latter has an Explorer app for poking around the HDD and collecting files, a CMD window for doing a filelist and a registry editor that can export. Dump them all to a flashdrive marked "before". Then after doing a repair install, repeat the process and get files "after". Later on, 'Diff them to see exactly what changed ( if anything ), you will then have an absolute answer to the original question.P.S.
you will notice from that link that I was also trying to determine whether I could do the repair install directly from
the HDD. That means copying the full updated SP1 ISO to the HDD and executing it from there without using an optical. The answer was yes, it works. But again, that is Win7. Now it should be do-able for WinXP considering that there are ways to install from a flashdrive ( and I believe from a HDD ), but I can't recall ever trying it. I suggest that experiment might be done separately to not make it too complicated. But the good news is that if you work from a cloned copy, you can always just start over with another clone if necessary. I would never do this on the one and only system disk though.