I brought parts to build a new computer I put it all together the fans and motherboard lights came on but there is black screen and no post. I have internal speaker and there was no beep. I think it is the motherboard or CPU as I bought them used. I also bought the ram used but I don't think that the problem as there would be a beep and it is consair which is a good brand. Please help as only eleven days until I return is no longer possible