The system actually recognizes the factory installed 1TB hdd just fine with all the UEFI stuff enabled (which is frustrating as all heck). I literally just reverted from legacy boot back to UEFI boot, re-installed the hdd, and it booted right up. However, when entering the F12 boot menu, it still won't recognize either of my bootable flash drives no matter which of the 3 USB ports I plug it/them into. It would seem they format these hdds outside the actual machines they go into (even though that didn't work for me).
Also, no eSATA port.
[Update] Apparently Windows 10 Media Creation Tool (MCT) creates bootable flash drives differently than using the Win7 USB/DVD Download Tool with the Win10 .iso image. Unfortunately the Win10 MCT is buggy as all get out. Errored out over a dozen times on my main machine while trying to create a bootable flash drive (and there's no option to use the Win10 .iso to create a flash drive, you literally have to download the temp .iso every time you try), so I figured using the Win7 tool with the Win10 .iso would be fine. It actually worked and booted fine on my main rig, as well as a spare laptop I have lying around, but not the new Dell laptop. Anyway, I was able to get the Win10 MCT to work on the spare laptop to create a flash drive that the Dell will recognize.......6 hours later.....
Main: i5-3570K, ASRock Z77 Pro4-M, MSI RX480 8G, 500GB Crucial BX100, 2 TB Samsung EcoGreen F4, 16GB 1600MHz G.Skill @1.25V, EVGA 550-G2, Silverstone PS07B
HTPC: A8-5600K, MSI FM2-A75IA-E53, 4TB Seagate SSHD, 8GB 1866MHz G.Skill, Crosley D-25 Case Mod