The problem occurred Saturday afternoon during a website download that coincided with an Acrobat Flash Player update download. The first indication of a problem was with the Flash Player download which stopped in mid-stream, then was noted by Security Essentials as a suspicious file. SE said it had cleaned the file, but things went downhill when Flash Player started to install. I can't recall exactly what occured or the sequence, but IE started locking up, then problems started with Windows. I was able uninstall, then reinstall IE. Then I had to uninstall and reinstall Security Essentials. But by this time Windows had been corrupted, which is when Bugbatter, then you became involved.
Now for the "good" news. The DVD drive has gone belly-up with a firm hardware communication failure, confirmed by both external and internal diagnostics. Apparently the DVD drive comm circuit had become marginal and was gradually approaching complete failure, which was causing the scf process to not complete, but producing different symptoms each time I retried it.
So...since the Optiplex is five years old, out of warranty, needing at least a replacement DVD drive, and a Windows reinstall, I figure I'll go ahead and replace it. That way I can transfer the backed up files from the network drive and the e-mail files from the Optiplex HD in the enclosure.
There are times that you must stop your losses, weigh your costs, and go forward.
Thanks for all your help. You certainly went out of your way, and I appreciate that. BTW, I'm very impressed with the AVIRA Rescue System.