Thanks for the response. Things have improved since I posted, but I'm still getting error messages. I don't have immediate access to the machine anymore - it's my sister's, and she needed it back. The good news is that I have gotten some Windows Updates since I posted. What seemed to work to get that going was following a suggestion I believe you made to someone else, following the process at
Search for Windows Updates takes forever? - A possible solution. After doing that successfully, I have gotten Window Updates. I still get an error message when I go to Windows Update in Control Panel - Windows 10 couldn't be installed, Error(s) found: C1900101-30018. CheckSUR.log still shows errors, as does SFCFix.txt. Below are the contents of SFCFix.txt. I don't know if these problems are just cosmetic, or are actual problems. If they're just cosmetic, I guess we won't worry about them. Avast! was uninstalled.
SFCFix version 3.0.0.0 by niemiro.
Start time: 2016-12-10 17:25:02.206
Microsoft Windows 7 Service Pack 1 - amd64
Not using a script file.
AutoAnalysis::
SUMMARY: Some corruptions could not be fixed automatically. Seek advice from helper or sysnative.com.
CBS & SFC total detected corruption count: 0
CBS & SFC total unimportant corruption count: 0
CBS & SFC total fixed corruption count: 0
SURT total detected corruption count: 16
SURT total unimportant corruption count: 0
SURT total fixed corruption count: 0
AutoAnalysis:: directive completed successfully.
Successfully processed all directives.
SFCFix version 3.0.0.0 by niemiro has completed.
Currently storing 1 datablocks.
Finish time: 2016-12-10 17:25:58.555
----------------------EOF-----------------------
