These are the basic steps that you need to follow.

Power Drain test for laptop.

If your computer is not having the inbuilt battery follow these steps.

1.  Turn off the laptop.  Unplug all the cables and devices including power cable.

2.  Remove the battery if it is not inbuilt.

3.  Hold the power button for 50 seconds.

4.  Connect all the cables back

5.  Turn on the computer.

Steps to remove the battery.

1.  Turn off the computer.   Remove all the cables and devices including power cable

2.  Turn the laptop upside down.  Flip the laptop.  On the back of laptop there will be a unlock switch.  You need to move the switch to the left or right and then you need to pull the battery door out.  

If your computer is having an inbuilt battery follow these steps.

Power Drain test.

1.  Turn off the laptop.  Unplug all the cables and devices including power cable.

Flip the laptop.  On the back of the laptop there will be a tiny hole.  It is called a battery reset hole.  There will be a battery symbol right next to the hole.

2. You need to insert a paper clip or small pin gently inside the hole and hold it for    30 seconds. 

3. Plug all the cables back and turn on the computer.

Step 2

Bios Defaults.

1. Turn on the computer and keep on tapping f2.  It will go to bios setup utility

2. Press f9 once on the bios setup screen.   It will show you bios defaults.  Please press yes.

3. Press f10 on the bios setup screen.  It will show you "yes" to save the changes.  Please press yes.

Computer will automatically restart and it will load windows..

Check how the keyboard is working fine now...

Step 3

Fix 3: Remove the battery

If restarting your laptop can’t solve your problem, try this: 

1)  Press on the power button for a few second to shut down your laptop.

2) Remove the battery of your laptop.

3) Wait for a while, then reboot your laptop connecting with AC power cord directly.

4) Try to type on your keyboard to see if it works.

Fix 4: Update your keyboard driver

Your laptop keyboard not working issue is also probably being caused by driver issues. 

Try windows + x - click on device manager  or press the window key + r - type devmgmt.msc on run windows

Expand Keyboard

Right click on keyboard driver - click on update.    Restart the computer and check

Fix 5 

Your laptop keyboard not working issue is also probably being caused by driver issues. 

Try windows + x - click on device manager  or press the window key + r - type devmgmt.msc on run windows

Expand Keyboard

Right click on keyboard driver - click on uninstall.    Restart the computer and check

Fix 6

Try to use an alternative usb keyboard and check.   If your alternative keyboard is working fine then it is the issue with your inbuilt keyboard

Fix 7

Sometimes the user you are using might be corrupted.   Try to login as a differrent user..

Create a local user account

1. Select the Start  button, select Settings  > Accounts  and then select Family & other users. (In some editions of Windows you'll see Other users.) 
2. Select Add someone else to this PC.
3. Select I don't have this person's sign-in information, and on the next page, select Add a user without a Microsoft account.
4. Enter a user name, password, password hint or choose security questions, and then select Next.

Change a local user account to an administrator account

1. Under Settings  > Accounts  > Family & other users, select the account owner name, then select Change account type.
2. Under Account type, select Administrator and OK.
3. Sign in with the new administrator account.

Restart the computer and check.   The keyboard should work fine now.

If the above steps are helpful for you please click "like"

If the above steps resolves your issue please click "yes"