I want to change the function of my F1-F12 keys?

Alright so my laptop is a newer model on a newer OS (8.1). I have come to the realization that my F1-F12 keys work backwards. When I press the F1 key it mutes my computer as opposed to doing it when I press the FN key. For a while I didn't mind, however, when I got into computer gaming it really started ticking me off. I have to hold the FN button whenever I want to use an ingame bind. This INFURIATES me, I can't even tell you how many guides I have looked on for an answer and no solution has worked. My computer won't allow me to access the Bootup OS setup screen (there's no option to) and I can't use a "One Key Recovery" button because I don't have one. I'm at wit s end, I'm just a few incorrect guides away from taping the d*mn FN button down.
I'm running a Lenovo laptop on an Intel Core i5 (64-bit) with a Windows 8.1 OS

Unless there's an option in the BIOS to revert to the standard layout there isn't anything you can do

Windows 8.1 lets you restart the PC to enter the UEFI firmware settings (A.K.A. BIOS or CMOS Setup).

- Press the Windows key + C, or swipe in from the right edge of the screen to open your Charms.
- Click Settings.
- Click Change PC Settings.
- Click Update and recovery, then select Recovery.
- To the right beneath Advanced Startup, click Restart now.
- Once the boot menu appears, select Troubleshoot.
- In the Troubleshoot menu, select Advanced options.
- In the Advanced options menu, click UEFI Firmware Settings.
- Click Restart. The system will restart and enter UEFI (BIOS).