I'm not a hundred percent sure what the problem is however to answer your second question yes, the graphics card will work in all PCIe slots on the board as long as they are the longer ones although the best slot to put the video card into is the first one because it has the fastest data transfer rate. I would suggest that your perform a test boot with the graphics card in another slot if it works then you can assume that your PCIe slot 1 is damaged. To answer your first question the problem sounds like either a video problem, a ram problem, or a PSU problem so I would assess those components first if I were you.