I encountered a weird issue where my keyboard would stop working on my "gl503V" Asus laptop, it can sometimes happen after an hour and sometimes wont happen at all no matter what i use the laptop for, a quick restart solves the problem but it is getting irritating, the laptop is less then a year old and fairly new, the drivers are up to date.
Is there a hotkey you're accidentally hitting that's disabling the keyboard? Any third party software installed that might be causing it?
If it's within warranty, contact Asus. They may ask you to reset the computer to its factory state, in which case you need to backup your data first (you'll have to reinstall updates and programs). If that doesn't fix it, then you likely have an intermittent hardware fault that they'll need to take care of.