Psu said boom, switched and now screen is black

Hi,

My psu said boom, and after i switched it, my pc boots but the screen stays black(no signal), my gpu works(tested on another pc) but im not sure if my mobo also went, all the lights work and every fan is working too but screen stays black when using my gpu on my pc(that had the psu going boom), ive tried to take everything out and put a part in, boot up, shutdown, next part in etc. But nothing happens :( help!