Before uninstalling/re-installing, try resetting Vegas Pro back to its default (factory) settings via the procedure outlined here making sure to clear the cache.

However, this will remove custom settings.

But before resetting - in the Options drop-down menu, there are 'Export Preferences' and 'Import Preferences' options so you can export the settings to a folder of your choice. Otherwise, I don't think that there is an easily accessible folder under Program Files recording each and every setting; rather, many settings are saved within various folders in the registry.

Most video plugins should still appear in Vegas Pro after a reset without a problem, but audio VST plugins will likely need to be reset via Options/Preferences/VST Effects - but this is an easy process.

Simply uninstalling/re-installing Vegas Pro will usually maintain most custom preferences, but as that process doesn't clear the cache it does not always solve many problems experienced in Vegas Pro whichcan usually be solved with a reset back to default settings.