HP Pavilion 15-ab030tx . Shift-quote key combo not working (Windows 10

Windows 10 Home latest version. I have a USA standard keyboard (I purchased the laptop in India in 2015). When my keyboard was working I would press "Shift - single quote" to get the double quote character. For some reason this key combo is now not working. Now when I press "Shift - single quote" I get nothing. When I press the single quote key that works fine; for example ' ' ' ' '
I downloaded and ran the HP Diagnostic tool and ran the keyboard diagnostic and it said my keyboard was fine. But the tool didn’t have a way to test key combos.
Any ideas how to fix this problem? I have to now jump thru some hoops to get the double quote character.
PS: I checked and the keyboard driver is up to date.

AndreTen said:

Did you by any chance changed kb layout to US international?

Good question. No, I didn't change the layout. In India laptops seem to all come default with standard USA keyboard.

I tried remapping the key combo, but from what I can see remappers (like Sharp Keys) aren't able to remap shift key combos.

AndreTen said:

If you didn't change it, try to add any other keyboard layout, remove US standard, and then add US standard back and change to it back.

Good idea, I'll try it. Thx. Your suggestion implies that if I change the keyboard layout, it's easy to change it back. Is that true? Can changing and reverting the keyboard layout create problems?

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AndreTen said:

MS powertoys recently add new powertoy - key remap - you could try it. I have no idea if it works or not

I did try it but it doesn't allow to remap a shift-key combo.

Try this test. It's a bit fiddly to use for shift-key combos but worked well enough to prove functionality.
Try ' key, then shift and finally shift + ' key to gauge results.

Keyboard Event Viewer

'' Check if you don't have anything else, ''

No, no other keyboard layout in my list. I added some and switched kb layouts and switched back to US but that didn't fix any of the kb issues. Now I only have US kb in my list.

I ran sfc/scannow and it found and repaired some corrupt files. But no changes to my kb problems. Still there.

My laptop seems to be running fine except for these kb issues.

AndreTen said:

Cam you try the link posted by W10tweaker above. Click on Shift, then ', and then combo.
Please post a picture of results.

Sure, here it is. Pressed left shift key, then right shift key, then left shift + single quote key, then right shift + single quote key. As you can see, when I hold down shift key (5 & 6, then 7 & 8) and press single quote key, it's like the press of the single quote key doesn't register at all. But when I only press the single quote key, it registers fine, as you can see.