Lenovo Thinkserver Windows cannot be installed to this disk. This computer's hardware may not support booting to this disk. Ensure that the disk's controller is enabled in the computer's BIOS menu

When trying to install Windows Server 2012 R2 Standard, I cancelled (red X after installation started) the first installation because I accidentally chose the wrong partition when starting the installation, so this brought me back to the install menu, I tried to delete all the partitions and start repartitioning (I wanted a 50gb, 50gb, and remainder (467GB or something, from the 600GB Raid I had).  It would not let me delete the 467GB partition, and showed it was using a little bit of space.  It said the partition was in use, so I assumed that since I hadn't rebooted since cancelling the installation, that the first install had left it in use.  So I proceeded to go back to the first install menu and chose Repair instead (no reboot in between yet).  Using diskpart I tried to delete the partition once again, and I couldn't.  There was a folder and a winPE swap file on the partition.  At this point I figured I had to reboot to get any further.

I rebooted, proceeded through the install steps to the partitioning screen again, was then able to delete the partition, but when trying to create a new partition, it created it, but didn't put any of the regular special partitions in front of it... I knew something was wrong at this point, and after creating a new 50GB partition, there was a message at the bottom of the install window stating "Windows can't be installed on this drive. (Show Details)" and clicking details showed the next error window:

Windows Setup
Windows cannot be installed to this disk. This computer's hardware may not support booting to this disk. Ensure that the disk's controller is enabled in the computer's BIOS menu.

At this point I'm starting to get frustrated.  I go into the windows repair options, run a command prompt, run diskpart, delete all the partitions (if any), try a "select disk 0" or whichever disk you are trying to use ("list disk"), "clean disk".  I'm thinking this is going to cure everything.

I reboot back into the windows install but get the same message at the partitioning screen.

I'm stumped, googling doesn't find too much, other then one entry for SAN's and similar systems where a flag may have to be set manually to allow windows to install to the disk (over-riding a security/safety feature), I try using diskpart to see if I can set this option but can't find a way, and try setting Boot Disk to yes using diskpart, but can't seem to do that or find how to do that either.

I revert back to trying to re-initialize the RAID-10 I've created on the 720ix raid controller that's built into the Lenovo Thinkserver TD350 server, this doesn't seem to help.  I try resetting the Virtual disk (erasing it), etc etc

Finally 2 hours into this endeavour I go back into the TDM (Thinkserver Deployment M....), and stumble upon the deployment tab/menu option that allows me to pick all my Windows options (partition, windows key, admin password, etc) and proceeds to do an automated install of Windows onto the Raid (one minor issue, it wouldn't let me create a partition smaller than 67GB for installing on, and I had only chosen one role (Hyper-V)... I was planning to do it with 50GB, oh well.

Before stumbling on the automated deployment tool in the bios, I was prepared to attempt clearing the Raid using Linux (in case windows MBR or something was still on the drive)... I don't really think this would have helped, but I was grasping at straws at this point, and wondering what had changed from the initial successful attempt to install windows (which I so wrongly chose to cancel apparently), and now... at this point I had reset bios settings, tried to see if there was a specific option to set the raid controller to a bootable device (thinking this was causing the error message during the partitioning and install phase)...

All I know is that at this point, the automated deployment I did from the Bios seemed to get things back in order again... I can't explain why it was failing to allow me create new partitions and continue the installation.