XPS 8500 will not boot after GPU upgrade

Hello all

I have a XPS8500 (3rd gen i5, 12gb ram, windows 10).  I installed a 600W power supply and replaced the AMD HD 7500 GPU with a Zotac GTX970. 

It was my first time doing this but I had some purchasing guidance from one of the pros at microcenter and install seemed very straight forward based on what I read. Everything went in fine and fit properly. I followed the directions to uninstall the existing GPU driver before replacing and download the latest driver for the new card but not install it. 

When I press the power button the boot screen loads (shows the Dell logo and blue progress bar, so I know the display works). Once the progress bar is full nothing happens and after about 30 seconds I get a beep from inside the case. Pressing F2 or F12 in the boot screen does nothing and makes ticking sounds if you press it after the beep starts. I did what trouble shooting I could but I am stumped.  To me it seems like the OS isn't loading.

I checked all of the power connections, they are all correct and tight. All of the SATA cables and such are tight. I put my ear to the HD on power up and I can hear it wind up. The HD makes a slightly different sound when it starts spinning, I don't know if that means anything... Whats going on here???

Thank you in advance,

Marc