If your certain the .dll is installed correctly, you’ve verified by looking in explorer and not confused the 64 and non 64 bit (Cubase will blacklist the 32 bit version if it’s there). In cubase try to find it in the plugin manager, looked in blacklist list.
If none of that helped then you can try deleting the cubase plugin blacklist file manually at /appdata/roaming/steinberg/vst2plugin blacklist. that will force cubase to rebuild.
ps. if you have other plugin installation concerns check out this handy app ultimate plugin tool http://ultimateoutsider.com/downloads/UltimatePluginToolSetup.exe