Had a bit of a heart stopper with my Surface 3 Pro refusing to boot past the initial screen shown above.
Long story short, this site provided the solution:
This is what worked for me:
Solution 3: Two-button shutdown (Surface Pro models only)
Don’t use this process on Surface RT, Surface 2, or Surface 3.
Use this two-button shutdown process to ensure that your Surface is turned off completely. Here’s how:
Press and hold the power button on your Surface for 30 seconds and then release it.
Press and hold the volume-up button and the power button at the same time for at least 15 seconds and then release both.
The screen may flash the Surface logo, but continue holding the buttons down for at least 15 seconds.
After you release the buttons, wait 10 seconds.
Press and release the power button to turn your Surface back on.
Phew! So if you didn’t know there is a two button process to ensure the Surface Pro 3 is off completely!
Hoppefully, this get someone out of a similar jam and prevents them from trying lots and lots of things before discovering this process.