Dell XPS 8300 Video Card Upgrade issues

Hey. I've had experience upgrading the stock graphics card to a Nvidia 650TI, but i've decided to upgrade again. This time, i've upgraded from the Nvidia to a Radeon RX560. The issue is, the card will not send signal to the display while it is plugged into the computer. I have checked to make sure that all the pins are connected, but there is still the issue. I've also noticed that the computer has issues finding my keyboard/mouse while the new card is in.

I tested to make sure that the card was not DOA, but it seems to be working fine on my brother's system. This leads me to believe that it may be an issue with either the BIOS or the PSU. I'm afraid to install the new drivers without having the card plugged in as i might lock myself out of visuals while using my older card, which is currently my only method of viewing the system.

Does anyone have experience upgrading this system to the RX560? Any ideas what the problem here might be?