I doubt if it's some shortcut.

So a few experiments:
- Does it appear if you boot from the Windows 10 install disc or stick (free to make using the Media Creation Tool).
- Does it appear if you boot into Safe Mode (that's different in Windows 10 from older OS'es)?
- Does it appear in the BIOS setup?
- Does it appear if you boot into Linux (disc or stick, free to make)

And more about your system:
- Do you use the video processing in the CPU (IntelHD or so) or do you use a separate videocard?
- Connected VGA, HDMI or DVI?
- Same on another monitor?