@NickHod42 it sounds to me like you have something interfering with the load/initialization process. The first step I would suggest is to disable (temporarily) any anti-virus or malware software you have running. If this allows you to start up then you can re-enable the software but will need to provide permissions to allow MSFS to do its thing.
FYI:
Contrary to what other personal preferences may be. If you had a working copy when things went sideways, it means that something in your system has changed. Drivers and security software are constantly being updated as are background apps. Renistalling Windows will not roll back those changes. You will end up with the latest versions. One of which may be the reason for your grief, so no upside there.
File corruption is a rare thing that usually only happens when the system terminates abnormally. Power outages or the dog pulling the plug. Forced termination on CTRL+ALT+DEL can occasionally cause data corruption but as this will only be on files that are being changed on the fly such as word docs or database records, it is unlikely that would have any effect on your MSFS or Win 10 files. PLEASE do not resort to Uninstall/Reinstall except as a last resort. If not done correctly this is how we get a messy registry and impossible to find bugs.