just picked up a R7800 to replace my MSI 6670. Installed the card to PCI 16 slot plugged in the 2 power supply connectors to the card from my 500 watt PS. Set bios to PCI 16. Can hear HD come up BUT no display (no signal) using the digital outs (BOTH) or from HDMI (new cable).Used 2 known working monitors. Any suggestions?