i had an installation running yesterday and accidently saved the project while one graphicscard output was set to fullscreen. after reloading the patch all renderers were greyed out and there was no way to get them working again. even deleting them didn’t help instantly. the way to get the patch working again was deleting all renderers (EX9), save the patch and restart vvvv again and adding the renderers.
a friend of mine had a similar problem…we are using the same type of machine (dell dimension 8400, ati x800SE) so it might be connected to some hardware thing.