VST2 vs VST3 probs -- I just built a new computer and

where my previous plugins were mostly VST2 I’ve installed VST3 this time. Evidently because of that, Cubase can’t locate plugins for projects I’ve worked on and I am guessing all settings for those plugins.

If I go back and install the VST2 versions will I be able to get going again?

I don’t see why not, could always just try with one plugin, if old project finds it, install the others. You’ve lost any custom presets though unless you backed them up first too.