My personal steps:
#1-trash prefs and test.
If its still not working, proceed as follows:
1-uninstall the rogue plugins
2-trash prefs
3-install plugins(with freshly downloaded installers if you can find them)
Having said that, first, try those plugins in a blank session. If they work there, and you can save>close>re-open the session, you might get away with removing the plugins from the troubled session and re-instantiate them, maybe the corruption lies with the session and not the plugins directly).
