After a failed upgrade attempt involving a new motherboard, CPU and RAM, my monitors are no longer receiving any signal when my GPU is used on the old motherboard (+old CPU and old RAM). I tried reseating the RAM but it had no effect. The rest of my hardware seems to boot correctly, including the GPU.
The GPU is an EVGA GTX 560 ti, the monitors are connected via HDMI and DVI, and I'm basing the fact that it works off the fact that all the fans and LEDs, including the fans on the GPU, are running, and that all the USB ports are functional. It worked flawlessly before the upgrade attempt.