I don't think that the slot would be affected because you are running that 280x in the same slot and it is running fine (assumption). If you aren't running it in the same slot than I would put it in the slot that the 980 was in and if it doesn't work than the slot is damaged. Also, if your wife and son were getting blue screens it was probably something with their systems or the card. About the PSU, it looks like that PSU is more than big enough to run your system even when it's hella overclocked. However, anything could be faulty. The metallic smell is actually common when people get their 980 over 70C and it is just new card smell even though the card has been used.