The laptop types numbers instead of some letters. For example, when you press on the following keys J,K,L,U,I,O it types 1,2,3,4,5,6.
The keyboard has NumLock enabled.
Possible troubleshooting steps and repair solution:
You have NumLock function enabled on your laptop. Disable NumLock and you’ll get your letters back.
On some laptops simply press on NumLock button located somewhere in the top row. On other models, you can enable or disable NumLock through the Fn (function) key. Press and hold down the Fn key and at the same time press once on the NumLock key.