I have recently purchased a MSI Geforce GTX 750 TI alongside a 500w power supply to upgrade my Gateway DX4860-UB21P PC. After I installed the PSU, I attempted to install the GPU but once I boot up the PC there is no display on my monitor. When I uninstall the GPU and reboot the PC, it works just fine. I have tried installing the GPU 3 times, each time I try to connect the monitor to the GPU using both VGA and HDMI. Then I try connecting both the VGA and HDMI to my old ports which still doesn't work so long as the GPU is connected to my PC. As stated previously these ports are perfectly functional when the GPU is not installed to my PC. I've also tried booting the PC with the case open and the GPU's fan is working even though there is no display.