Hi,
Please do try these steps first.
- Go to Control Panel and look for Accessibility option
- Remove the check on Sticky keys, Filter keys and Toggle keys
- Reboot your laptop and see if it works.
If that doesn't work please do try these troubleshooting steps below.
You're keyboard should be using just 1 ribbon cable that connects it to the motherboard. I suggest to take the keyboard out again and make sure that the ribbon cable is properly seated in it's slot and hold down properly by it's retaining clip.