Help, What addon be causing my start menu to be a Blackscreen

I recently fixed my old desktop which has been sitting idle for a good while with all the custom content i’ve downloaded for it, and every time I’ve tried to play gmod the background comes up, and it goes totally black when the loading bar is supposed to pop up, and after it finishes loading it stays black, but the background music is playing and i can hear the button sounds, and I can’t see what could be fucking it up.