A strange issue I’ve encountered before is that sometimes if you hold the shift key down for too long, the keyboard stops typing certain characters, and can even refuse to type capital letters without having the caps lock key OFF. Usually, rebooting your machine does not fix this.
Example: You hold shift for too long, and then the keyboard doesn’t work as expected, even after a reboot.
Resolution: The simplest way to fix this is to hold both the left AND right shift keys down for a couple of seconds while the computer is fully booted up. If this somehow hasn’t fixed the issue, make sure you try the following:
Go to Control Panel
Open Accessibility Options
Click the Keyboard tab
Untick the boxes for Sticky Keys, Filter Keys and Toggle Keys.