I did this test: first thing, I removed my Hard Disk. Then I booted my Linux USB stick and it booted succesfully (EFI=on)! After doing that, I tried with my Windows 7 USB stick and it booted too. So I can say that Windows is causing the problem.
I've attached the screenshot you asked me.
Even though during the installation Windows created 2 little partitions (about 100 MB each) and the main C: drive, Disk Management show only one little partition.
It isn't always created but since you say you saw it during install the second MSI Reserved partition is hidden, most likely.
When you can boot media with your HD unplugged that won't otherwise boot it normally is resolved by wiping code from the HD. Even deleting all partitions will not wipe the boot sector of possibly conflicting code (most applicable in this case) or partition table. You'd really need to use Diskpart Clean Command .
I've never seen evidence in a case like this where the HD is clearly blocking media boot that it is caused he OS at all. More likely some conflict with old GRUB code.
You may be wipe the HD while it's plugged in by rebooting with the http://www.carrona.org/hddiag.html CD or Partition Wizard CD in the drive which should autostart. I'd test the HD with the long test anyway to be sure.
What is the HD diagnostics test results?
Try reformatting and writing the stick again. Use Option One in UEFI Bootable USB Flash Drive - Create in Windows which we know works for UEFI always. If it boots then the problem is the way the stick is written.
Try another stick.
I solved this problem by booting from USB using a hidden temporary boot menu. I wonder why in the user manual I couldn't find this menu; also, when I chatted with Samsung Support, they didn't told me about it either.
The Boot menu key for Samsung is F12.
Then it must be different on your model. Is everything OK now?
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