I guess you are having too much trouble using your keyboard while “Fn” key gets locked. If none of those key combination worked for you then this solution might work for you. So lets get straight to the steps to solution.
1. First of all press Window logo key to open start menu
2. Now press and hold the “shift” key and click on Restart
3. Now you will have this menu. Click on Troubleshoot.
4. Click on Advanced Option
5. Click on Firmware Settings
6. Click on Restart. It will reboot your system into BIOS/UEFI mode automatically. So do not press any buttons.
7. Now go to “Main” tab and go to the “Function key behavior” option.
8. Press Enter to choose options and set it to “Function key”.
9. Now press “F10” key to save this settings and exit the BIOS/UEFI mode and reboot your system.
Let me explain a little bit about Function key behavior option So it will not just resolve our issue but you will understand how this works so you will not have to find reference on the internet like this if this happens again in future. So in your keyboard “F1…F12” keys are called your “Function Keys”. You will see symbols on some of this keys like volume controls, brightness control, airplane mode, etc. This are your “Media Keys”. So If you set your function key behavior to “Media Key” then all this Function keys work as media keys by default So they work like their symbols says. And to use the “F mode (F1,F2…F12)” on those keys you have to press the “Fn” Key. And wise versa If you set the behavior to “Function key” they will work as “F mode (F1,F2…F12)” by default and to use the media(symbols) keys you have to press the “Fn” key.
OK But why this steps, we can also open BIOS/UEFI by restarting the computer and press the BIOS keys right??? Well YES but it might not work in all scenario (at least in my case it didn’t work). Because your function keys are set to media keys so you cant open BIOS/UEFI mode using BIOS key. I hope this will resolve your issue. Regards!!!