Please do try these troubleshooting steps that may help.
- Click Start and search for Device Manager
- Once Device Manager is open expand Keyboard and right click on the driver of Keyboard and click on Uninstall.
- Reboot your laptop and it should reinstall the keyboard driver back automatically then try it again.
Yes you can roll it back from Windows 10 to Windows 7.
- Click Start then select Settings
- Select Update & Security and click on Recovery
- You should see Go back to Windows 7 select it that should roll it back.