Re: SFC Corruption
I ran Memtest86+ with all four memory modules installed and got errors. I removed one of the modules and tested again. Again I got errors. I repeated the procedure twice more and got errors. Finally, with just one of the modules remaining, Memtest86+ reported no errors. Of the three modules I had removed, one was an unbranded generic, as was the remaining module. I guessed that it was the bad module and reinstalled the two name-brand modules. Memtest86+ reported no errors. I now have six GB of ram installed in my system and everything appears normal. Windows Update reports that it is up-to-date. Chkdsk and SFC are reporting no errors. I will be purchasing another 2 GB ram module (about $20) to bring my computer back up to 8 GB.
I have used PCs since they first became available in the 1980's. This is the first time I have ever had a problem with ram.
I guess we can mark this thread "solved." Many thanks again Brian for your efforts.