Hello everyone. I currently own a Mac Pro 4,1 w/ single 2.66 quad-core, ATI 5870, 24gig Ram with multiple hard drives. Every attempt to install WIN 7 64-bit onto any single one of my hard drives causes my machine to immediate fall into sleep mode once I proceed with the basic black and white screen of Win 7 drivers installed. I've made attempts at reinstalling Mountain Lion onto a new HD with nothing but the same results. Any ideas of what I'm doing wrong? 
Partitioning the drive is no issue and downloading the needed drivers onto my flash drive is no issue either...
Partitioning the drive is no issue and downloading the needed drivers onto my flash drive is no issue either...