I suppose you could go into the preferences and temporarily rename the folders that Cubase scans. Find the name of the scanned VST2 and 3 folders in the link I attached. Good luck.
i once did a regedit to force cubase to use my custom default vst2 directory. i made a mistake in the path entry and cubase then scanned my whole drive and attempted to load all dlls. you negelcted to mention anything about your OS. hope this helps.