[Bloody Sam Roberts]

I agree with the suggestion for a clean install.

Side question on that subject;

Is it possible to do a 'repair' install of XP so that it simply updates OS files, etc. and does not wipe the drive so that all personal data and installed programs are gone?

I've done it once before and it got rid of all non-Windows data.

I have searched and seen about a 50-50 mix of those who say it is non-invasive versus those who say otherwise.

I have a PC that says "WinXP can't start because of corrupted or missing C:\windows\system32\config".

I've tried running the Recovery Console from XP disk and chkdsk and Windows does start but after shutdown, the next boot does not run Windows. Only the same error message. I'm thinking a re-install of WinXP would fix it...but not at the expense of all my installed programs.

[E. Pluribus Unum]

If you have stuff you don’t want to lose, you should have it backed up anyway. I wouldn’t take the risk.

[Scutter]

It has been very long since I used XP, so I am not sure. I do see lots of articles on this topic, which you can find by searching Bing or Google for "XP repair install" or similar query. For example, here is one article that I found.

Good luck with it, and please don't forget to back up your data first!