My Screen is black when i turn on vendetta. I can hear sounds when i press certain buttons, but the display is always just black.

I have had this. For me, it was because of the resolution being at a certain setting, so simply deleting config.ini in your Vendetta directory should changed your resolution setting to one that's most likely to work. This also means reconfiguring a few things, like graphics, video, and some parts of controls.

The defualt Vendetta directory paths are:
Windows: C:\Program Files\Guild Software\Vendetta
Linux: ~/.vendetta
Mac: The place you downloaded Vendetta.app to. It's a folder.

Do other OpenGL apps work?

It's usually preferable to rename a configuration file rather than deleting outright [i.e. config.in_, config.ini.old, or config.old]. Then, if you find that the newly created INI file does not fix the problem, you can just remove the new INI file, rename the old INI and not have to recreate your custom settings and bindings all over again.