Why is my laptop keyboard not working and how can I fix it?

I was in the middle of a project when I suddenly realized that my laptop keyboard wasn't responding at all. At first, I thought it was just a matter of dust or dirt getting in the way, so I tried gently brushing it off. But when that didn't work, I started to get concerned. I've used this laptop for years and have never had any issues with the keyboard before. Has anyone else experienced something like this? Any suggestions on how to fix the problem would be greatly appreciated.