Sorry if I wasn't being clear enough.
With the new card installed (without PCIe cables) it will power on. All case fans and LEDs turn on as does the GPU LEDs and fan. I get signal to the monitor with the message that asks me to power down and connect the PCIe cable. Once the cables are connected it will not power on at all, no fans, no leds, no nothing. I've tried a single cable to the PSU using the 8pin and the 6pin. Tried 2x cables, one for the 8pin and the other for the 6pin (tried switching them around and new cables but none seem to be working).
I've tried everything that helpful members of the forum have suggested but nothing seems to work. The only thing I haven't been able to do is test the card in a different working machine.