Push the keys windows + r to open the run dialog and type regedit.
The Registry Editor will open
Backup the registry (file, Export…, export range = all)
Find and click on VST
You will see two entries one says default – (value not set) and the other might for example say VSTPluginsPath – C:\Program Files\Steinberg\Cubase 6\VstPlugins double click on this one.
Modify the data to the desired folder address (" C:\VST\") (or so...)