How to install an O/S on a headless computer.
I purchased a HP Data Vault which came with Windows Home Server but of course not the current version of WHS. I then bought the OEM version of Windows Home Server 2011. The difficulty came in being able to install a new O/S on a server that has no optical drive and no video port. The optical drive was not such a big deal - it's easy to connect an external usb optical drive. The video issue was a little bigger of a deal. You might want to try a USB to VGA adapter but it needs to install WINDOWS drivers which of course are not relavant when you haven't yet gotten windows installed. I read some forums that talked about removing the system volume mounting it in a computer with video and then running the O/S install up until the point of the first reboot, next return the drive to the Data Vault server. I did this but got stuck accessing the server remotely when I kept getting prompted for the Product Key and then being shot down by an Invalid Product Key error message - this even when I called MSFT Tech Support and they generated TWO additional Product Keys for me.
Kevin Royalty gave me the suggestion that got things back on track and working great. I created an .ISO file from the Windows Home Server installation disk. I used this and the Windows 7 USB DVD Download Tool and a WHS Answer file (cfg.ini) to create a WHS Self Installing Boot USB Key. Boot from this USB key and voila - a headless machine installed with the new O/S.