after searching the threads i've found similar issues, but nothing quite the same. I have 2006 mac pro. I just installed a 5770 card about a month ago. Everything worked fine until yesterday. When i try to wake it from sleep mode i can hear everything coming on but my monitor stays black. I run windows on it's own drive and it has issues when coming out of sleep too, but instead of the monitor being black it completly restarts. Any ideas what to do? as soon as i can i will try and older video card to see if i still have the same issues and if not, I'm guessing card is defective.