As Neil said, try the helpline first but if you aren’t in the right Timezone to do this then there are things you can try.
That not starting issue happens occasionally but usually on V9 rather than later versions. If a reboot doesn’t work then in sequence you shoould:
1) Try a 2020 Registry Reset (you will lose your preferences and have to set them up again)
2) Try a Basic Uninstall then re-install. This will keep your catalogs and most settings
3) Try a Complete Uninstall then re-install. You will have to re-enter your preferences and reload all your catalogues.
This presumes you don’t have computer issues such as a dying hard disk or a Windows 10 (Anniversary) update that have screwed 2020 up.