How do I turn my function keys back on? [Windows 8.1 Devices and Drivers]

I have Windows 8.1 64 bit color Asus Notebook X551MAV-HCL1201E an I have been trying to get my Function Key's to work when I hit F1 - F12 an for them to work as of right now I have to keep hitting my fn key on my key board an I have tried the fn+num lk , fn+shift+num lk to get my function key's back.

Ans:
1.
Hello,
Thank you for posting your question on Microsoft community.
I would like to know some information about the issue so that we could help you better.
Did you make any hardware or software changes to your computer prior to the issue?
I appreciate you for providing details about the issue and your efforts towards resolving it.
This issue may occur either due to corrupt device drivers or incorrect device settings.
I would suggest you to try following methods and check if it helps.
Method 1:
Run hardware and devices troubleshooter and check. Please follow these steps:
a. Press Windows + W keys, type troubleshooting in the search box and press Enter.
b. Click "View all" and then click "Hardware and Devices".
c. Click "Next" and follow on-screen instructions.
If it does not help, use method 2.
Method 2:
Please use suggestions provided in this article and check the issue.
Refer:
Windows 8 Troubleshooting: Keyboards
http://www.microsoft.com/hardware/en-us/help/windows-8/troubleshooting/keyboard/using-keys
I hope this information helps.
Please do let us know if you need any further assistance.
Thank you

2.
I would suggest you to update chipset drivers and BIOS and check the issue. Please also install "Keyboard Device Filter Utility".
Please refer the following links:
Keyboard Device Filter Utility
http://dlcdnet.asus.com/pub/ASUS/nb/DriversForWin8.1/KBFilter/KBFilter_Win81_64_VER1005.zip
Chipset
http://dlcdnet.asus.com/pub/ASUS/nb/DriversForWin8.1/Chipset/Chipset_Intel_Win81_64_VER9441006.zip
BIOS
http://dlcdnet.asus.com/pub/ASUS/nb/X551MA/X551MAAS513.zip
Note: Modifying BIOS/ complementary metal oxide semiconductor (CMOS) settings incorrectly can cause serious problems that may prevent your computer from booting properly. Microsoft cannot guarantee that any problems resulting from the configuring of BIOS/CMOS settings can be solved. Modifications of the settings are at your own risk.
Please keep us updated on the status of the issue.
Thank you