I was installing Windows Server 2012 on the HP N40L Micro Server and kept receiving the following error when creating a new installation partition:
"Windows installation encountered an unexpected error. Verify that the installation sources are accessible and restart the installation.
Error code 0xC0000005"
After swapping drives, SATA ports and running Memtest86+ I thought to unplug the SSD drive. The drive was connected and showed up in the BIOS, but mysteriously didn't show up as a possible target during the Windows Server 2012 installation. Unplugging the drive cleared up the issue.
Thought I'd throw this out there for those Googling around trying to solve a similar problem.