Hyper-V Program Manager
We just recently posted a Knowledge Base article (http://support.microsoft.com/kb/969556) that points to an Intel support article (http://support.intel.com/support/motherboards/server/sysmgmt/sb/CS-029944.htm) that may help you out if you are seeing a 'General access denied error' (0x80070005) when starting a virtual machine under Hyper-V.
The problem is caused by the Intel IPMI driver that is included in the One Boot Flash Update (OFU) utility, System Configuration Utility, Intel Active System Console, and Intel Server Management Pack. When this driver is installed it incorrectly modifies some security settings that prevent Hyper-V from accessing the storage for any virtual machines.
The above article provides a tool that resets these security settings back to an appropriate value.
I have Hyper-V R2 and I've been touched by the problem described above. However the tool from Intel claims that 'This fix is not required for this Windows version'.
You are going to need to contact Intel about this.
Big Thanks for pointing this out, was searching the net for this quite a while!
And Thanks to Intel for creating big disease with small effort...