Several different factors can cause the keyboard on your dell laptop to lock up. Sometimes it's something simple as a minor glitch and other times it's something more serious like a damaged keyboard. The good news is that there are some very easy ways to unlock the keyboard on your Dell laptop.
First, consider restarting your laptop. This will fix the issue and it's also a good idea to check the battery, as that may be running out of juice.
If you still can't type anything with the keyboard on your dell laptop, try updating the driver. The keyboard drivers are programs that allow your keyboard to communicate with other devices.
Another option is to disable the FN lock key, which is usually located on top of your numeric keypad. It's possible that you accidentally pressed this button by accident, which is why your keyboard isn't working.
However, disabling this key might not be a solution for your problem. The FN lock button is meant to let you access other keys at your request, but it's very easy for them to get locked up.
The easiest way to remove this lock is by pressing the FN key and the NumLock button at the same time. This will unlock the NumLock key and your keyboard should work again.