That's a bit worrisome if you didn't install anything. It could be the settings for Windows themselves, or it could mean malware is present.
I'm seeing references to Error code: 0x6D9 being associated with a rootkit in some cases.
Suggest you scan with TDSSKiller to rule that possibility out. Even if you did a clean install, some rootkits can survive that unless you wipe the entire drive before reinstalling. Or perhaps one of your programs had malware when you reinstalled them.
When running TDSSKiller, launch the program, click on the blue text "Change Parameters" & check the box marked "Detect TDLFS File system." Click OK & then run the scan.
Also a scan with Malwarebytes would be a good idea to see if anything is present. The free version will work fine.
Malwarebytes | Free Anti-Malware & Internet Security Software