This is the cleanest way to wipe your Windows machine of Cubase VST. Click on the "uninstall" icon in the Cubase VST folder in the Steinberg Folder. Choose the "Custom" option when asked what kind of uninstall you’d like to do. Then proceed to click on "Select All" and "Next." When you’re almost finished click on "Yes to All" when prompted to delete the following shared files.
You’ll be informed the uninstall was successful and that a reboot is needed. Do not reboot the computer just yet as the Registry needs to be cleaned of Cubase VST
From the Start button, go to "Run and type in regedit in the "Open" box. When the System Registry editor opens, click on the + next to "H Key Local Machine.". Then click on the + next to Software. From this pull down set of folders, delete the ASIO, Steinberg, Syncrosoft and VST folders. When you are asked if you want to delete the keys, click on yes. Once these folders/keys are deleted, close the registry editor, reboot and the computer and reinstall Cubase VST form your CD Rom. This will give you the cleanest possible install. You may have to reinstall your sound card’s ASIO drivers.