While you're waiting for a pro to respond, I read your post and thought you might want to read the following MS knowledge-based article in the Help and Support feature: Windows File Protection. I actually got this article via a link inside another help article I was reading, but you should be able to type "Windows File Protection" in the Help search box and get to it.
Then go to: http://support.mocrososft.com/default.com/...kb;en-us;310747
There you can read about Windows "System File Checker Utility". I printed out a long time ago and have run the scans more than once. I'll type the key paragraph below:
To run the System File Checker (SFC) Utility in Windows XP, Click the Start button, then click Run, and type into the entry box : SFC /Scannow . Then click OK. The actual scan takes quite awhile, but is worth it, I think. If it finds any damaged, overwritten or altered files, it retrieves the correct version from the cache folder (%Systemroot%\System32\Dllcache) or the Windows installation source files (have your WinXP CD handy in case it prompts you to insert), and replaces the incorrect file with the correct one from the cache folder (or CD). It has never asked me to insert my Windows XP CD to date. You must be logged on with a computer administrator account to run SFC.
Hope this will be helpful.
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