Have you looked at the AV history to see if it removed ProcRunner4.exe?
Before you reinstall, you could try the “Modify/” option from the app list, if you choose Paratext 9 in Add/Remove programs, you should see a “Repair” option. Maybe that will help.
If you need to reinstall, you can remove Paratext via add/remove programs. You can leave your settings in place if you don’t want to have to enter your user code again. The user code (whether you keep it by not deleting your settings, or whether you delete settings then enter it again) is what give you your permissions and project access.