Shane, thanks for the advice.
1) After running the procedure at the first link you posted (using a full install DVD with SP1), I ran the command "sfc /scannow /offbootdir=d:\ /offwindir=d:\windows" at the prompt. However, I got the same message as always: "Windows Resource Protection could not start the repair service." Then I got a message that said (in effect) "we couldn't find any problems with your system drive, would y0u like to restart from a System Restore?", to which I replied, no thanks, and when I rebooted to Windows, everything was back to where it was (i.e., sfc still would not run). But now something new popped up: a dialog box that said:
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Proxy Authentication
Your proxy server requires a username and password. Contact your network administrator for the correct settings and supply your proxy username and password in the "Connection" section of Settings.
Proxy server: 0.0.0.0:0
Username:
Password:
Retry Cancel
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I never had or needed a proxy server before, I don't have a username or password for such a thing, and I couldn't get rid of this mindless dialog box, so I did a System Restore to back before I had run the procedure above. Everything after the S.R. is back to normal.
2) Followed the procedure in the second link, but -- as seems to be par for this course -- sfc still did/does not work.
I will just give up on sfc for now and wait for something to happen that definitely requires an in-place reinstall of Windows.
Thank you for your help!
Frank D