Running SFC /scannow repair sometimes finds 'corruption' it could not repair. Most of these are 'just in case' files or other crapola and nothing to be concerned about, but there are some that really need to be fixed. Found this great tool that does just that. Really does a great job. So before a OS reinstall, give this a shot.
1. Run SFC /scannow (file will be stored C:windows/logs/CBS)
2. Run SFCFIX (be patient, it takes longer than scannow)
3. SFCFIX file will appear on your desktop with results
Note: Before the program starts, it offers the choice of uploading the info to their servers for more complete diagnosis...I chose no.