Windows 10: Weird behaviour from keyboard and various software

Running Windows 10 on a desktop. Replicated with different keyboards. All of this happened yesterday

1. Shift key in Firefox causes LEAVE PAGE. But no effect in OpenOffice

2. Typing an entry into File Explorer tries to autocomplete but flashes the title and won't allow deleting characters unless Shift Key is held down
3. Hovering over the folder list in File Explorer causes scroll down which stops if the shift key is held down. On the body causes scroll left

4. Same behaviour on Start Screen
5. Holding the Ctrl key without a plus sign causes zoom in office

6. All drop down menus in FIREFOX and other apps appear for an instant then vanish and can't be accessed
Help please

:)

 

Weird PS/2 keyboard behaviour after installing KB3135173

Hi Radek,

Thank you for replying with the status of this issue.

Try installing the drivers in compatibility mode and check if it helps.

Refer the steps to install a driver in compatibility mode:

a. Right click on the setup file of the driver and select Properties

b. Select Compatibility Tab

c. Place a check mark next to Run this program in Compatibility mode and select the operating system accordingly from the drop down list

d. Let the driver to install and then check the functionality.

If you need any further assistance let us know and we would be glad to help you.

 

Weird PS/2 keyboard behaviour after installing KB3135173

Today I have installed the cumulative update KB3135173ssss. After that, my keyboard started acting weird - it either "thinks" Ctrl key is pressed, after resetting the computer it turns out that Shift stays on (although I do not press it and ssssssssssssssssssssssCsaps
Lock light is off). In the prior sentence you can see another example - I didn't press "S" key...ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss

ssssssssssssssssssssssssssssssssss

Assssnd asgaisn - I hasd to press "Esc"...

 

Are you sure the issue is in keyboard? Especially items 3 to 5 on your list sound as a mouse issue, broken / frozen scroll wheel. Easy to test if you have another mouse.

 

I had tried different keyboards and a different mouse and tried them in different USB ports. I also did a soft reboot. Nothing worked.
Then I unplugged all the USB devices and plugged them back in one at a time and it's all fixed - but I've no idea why.