I have an XPS 8500 with 16GB RAM and upgraded my GPU to A GEFORCE GTC 1660 as well as the power supply to a 600W. I've tried reseating it, and even tried booting with the BIOS downloaded from the Dell page for the 1660 but still just get the main BIOS load screen, then a single beeping followed by black screen and all the fans turn off. Single beeping continues. I'm at a loss now as to what else could be causing this.