The machine is a brand new Dell Precision m6500, Core i5, 8GB RAM. Windows Server 2008 R2 (fully patched) with Hyper-V Role Enabled. Virtualization options in the BIOS are ON, SpeedStep is OFF, couldn't find C1E option in the BIOS to turn it off (I also got the impression that SpeedStep is C1E, but the Intel Product site lists them as separate "features." shrug) The server stops responding without any apparent reason. I've tried testing in multiple scenarios, all of which result in a crash at seemingly random times: With the Server sitting idle, no apps running. Server sitting idle with a Virtual Machine running. Using a BurnInTest application There's no blue screen. It doesn't restart. The screen just sits there. The keyboard backlight still responds and comes on with input, but nothing on the screen changes. There are no errors in the error log. I have to hold down the power button to turn it off. Doing memory tests on bootup results in no errors with the memory. I have a second identical system and the same thing happens there too. I've dual-booted into Windows 7 Profession x64 on this system with no problems. Further testing has shown that the issue is definitely related to Windows Server 2008 R2 and Hyper-V as it appears the crashing does not happen when the services are not running. I've installed all hotfixes relating to this issue (that I could find): 975530, 979444, 979491, 976427 System is still crashing without response.