The problem doesn't seem to be hardware-related. I think the input methods are being mis-configured accidentally.
Can you please check if the default nature of the Fn key of your laptop is set to on or off? Normally you can turn on or off the Fn key (just like to do with Caps Lock) by pressing the Fn + Shift + NumLock keys together.
If this doesn't help, check the Fn key's default behavior in the BIOS setup of the laptop's motherboard.
If the issue persists, you should consider visiting the nearest service center and ask them to help you.