Question about XP Pro

If I were to re install XP pro over my existing Xp pro, will it re-format the hard drive or will it just fix the broken and missing files?

You'll get a choice. Provided you just install into the existing location and don't ask it to format, it won't.

That's not to say you shouldn't backup your data first, though. :)

You'd want to go past the first and second repair options til' you get the third that asks if you want to repair an existing installation. you will have to reget the updates but your files and settings should survive. But, as Tuttle said,backup anything you can't afford to lose first...

Boot up with the XP CD in the drive and let Setup run. Go past the "C" and "R" repair options by presssing Enter just as if you're doing a clean install and you'll eventually get an option to "Repair an existing installation". That's the one you want. If it asks about formatting you've gone wrong, so start over.

You'll get to keep your existing apps & settings, but you need to re-install SP2, Windows Updates & any unsigned drivers afterwards. NOTE: Be aware that you'll lose any protection from Blaster / Sasser type worms. Don't go online without a firewall, whether the built in Windows one or 3rd party.

How to perform a re-install of WinXP

Repair XP