I installed two new ATI 5770 in my computer last night. I had 1 5770 already installed. They were all working fine when I went to bed. I'm running Windows 7. When I woke up in the morning, the card I had already installed wouldn't send a signal to my monitor, until I restarted. After restart, my monitor is displaying properly. But, one of my 2 new cards isn't showing up in my device manager anymore. It's also not in the GUI Miner drop down menu. Anybody have any ideas about what might have happened?