Is the SM951 the NVMe ( MZVPV512HDGL-00000) version or the NGFF (MZHPV512HDGL-00000). I have the latter and yes it is a work of art trying to install windows 7 on it. Make sure all other hard drives are disconnected, leaving just CPU, RAM, Graphics card and SM951. In Bios restore all settings to default. In Advanced under PCH Storage configuration change SATA mode to AHCI. Enable CSM and set :- Boot Device Control > UEFI and Legacy OPROM; Boot from Storage Devices :> Legacy only. Boot from Network Devices: >Legacy Only. Boot from PCI-E/PCI Expansion Devices :> UEFI Driver First. Set Boot order: 1st> Samsung M.2 SM951 2nd> DVD -ROM. Save changes and Exit. Reboot: Now SM951 should show up in Boot order. Now either create a USB Boot disk that will boot to UEFI as I understand it only 64 Bit edition of Win 7 is supported on Booting in UEFI. The Windows install should see the Samsung SM951, ask you which disk to install on and everything should be ok. One thing that I had to do more than once was to format the M.2 and delete everything that was on it ( even though it was blank), don't ask me why, after this it accepted Windows 7. Sorry, this is late in coming, only just seen the query, hope this helps. P.s. I cannot claim any plaudits for this, I trawled the forums for the exact same info for my Asus Z97A-USB 3.1, my thanks go to a number of Suchewie to name but one M.2 slot on that board not up to speed, I stuck my M.2 on a Lycom DT-120 adapter. If all else fails, buy the 950, I will upgrade to that soon.