VGA and BOOT light seemingly coming on at random

I recently bought a Skytech archangel 4 because it was recommended by my friend, it works great!

Though at seemingly random times, I'll try to boot it up and the vga and boot lights come on?? Sometimes it's fixed with a simple reseat of the graphics card, but sometimes it just won't work

I'll try reseating the ram and graphics card when this happens but sometimes it just won't display on screen and shows these lights