Clean Windows 10 install, Ctrl+Backspace not working anywhere

Question

I have just done a clean install of Windows 10 on a new PC. Ctrl+Backspace isn't deleting the word to the left of the caret in any program (Notepad, Chrome [address bar and text boxes such as this one], Windows search, etc). On the other hand, Ctrl+Delete does work and deletes the word to the right of the caret. Alt+Delete (restore last deleted word) works in some places (Notepad), but not in others (Chrome, Windows search).

I don't know if it's relevant, buy I also installed a second keyboard scheme in Portuguese. I don't remember if I used the command before installing the second scheme, but the command doesn't work in either language.

I've thought of installing AutoHotKey to solve this, but given how standard a feature this command is, it really shouldn't be necessary.

EDIT: @Leathe suggested in the comments testing the On-Screen Keyboard to see if that works. It does. This implies that the problem is in the keyboard. However, it clearly isn't a trivial hardware issue (broken key, for instance) since each of the keys works properly: Backspace deletes the letter to the left of the caret and it deletes files in Explorer; Ctrl modifies the behavior of other keys (Ctrl+Delete, Ctrl+C, Ctrl+V all work as expected). It's just the sumation of both that is not behaving properly.

EDIT2: Using Key Scan Codes I checked how the PC is receiving the key strokes when entering these key combinations and have come up with very strange behavior.

Here's the program's output for Ctrl+C:

OnKeyDown, Key code=17, Control keys= Ctrl{Left}, Key name CTRL
OnKeyDown, Key code=67, Control keys= Ctrl{Left}, Key name c
OnKeyPress 
OnKeyup, Key code=67, Control keys= Ctrl{Left}, Key name c
OnKeyup, Key code=17, Control keys=, Key name CTRL

This is the same for every other combination (replacing the second and fourth lines to the respective key, obviously), with the exception of Ctrl+Backspace, which outputs

OnKeyDown, Key code=17, Control keys= Ctrl{Left}, Key name CTRL
OnKeyup, Key code=17, Control keys=, Key name CTRL

OnKeyDown, Key code=17, Control keys= Ctrl{Left}, Key name CTRL
OnKeyup, Key code=17, Control keys=, Key name CTRL

where the second and fourth lines occur when I press Backspace. For some reason, this specific combination replaces Backspace with a "raised the Ctrl key" action.

In fact, if I hold down any combination, the program displays

OnKeyDown, Key code=17, Control keys= Ctrl{Left}, Key name CTRL
OnKeyDown, Key code=67, Control keys= Ctrl{Left}, Key name c
OnKeyPress 
OnKeyDown, Key code=67, Control keys= Ctrl{Left}, Key name c
OnKeyPress 
OnKeyup, Key code=67, Control keys= Ctrl{Left}, Key name c
OnKeyup, Key code=17, Control keys=, Key name CTRL

where the OnKeyDown/OnKeyPress lines for C are repeated for as long as both keys are kept down. However, if I hold down Ctrl+Backspace, all I get is a single instance of

OnKeyDown, Key code=17, Control keys= Ctrl{Left}, Key name CTRL
OnKeyup, Key code=17, Control keys=, Key name CTRL

Meaning that, as far as the PC is concerned, I'm actually not pressing anything.

I'm really not sure how to solve this. I don't even think AutoHotKey would work in this situation since it seems that the Ctrl+Backspace combination simply doesn't appear to the computer.

Answer 1

I solved it. Just as soon as I posted the most recent edit, I remembered that I plugged the keyboard into a USB port tagged with HOTKEY, which is a special port which allows me to boot my computer via my keyboard and some other silly things.

Just to see if that could possibly have anything to do with it, I put my keyboard into another USB and that solved the issue. I then looked at my motherboard's manual (its an MSI Z170a M7) and for some absurd reason they set Ctrl+Backspace as the shortcut for their "HOTKEY function" which does some more silly things. Why they didn't choose literally any other combination, I have no idea. But, well, that solves it. Now I just need to find out if I can change the combination for that HOTKEY function or if I'll simply need to keep my keyboard in another USB port.

But that's a different matter.