Q: How do I find the hardware drivers for Windows 8.1

To install Windows, with the correct drivers, use Boot Camp Assistant. Or, use a virtual machine like Parallels, Fusion, or VirtualBox.

Erase the had drive and start over by reinstalling OSX. Then install Windows and the drivers correctly as I stated above.

Apple Communities may not be the best place for your question since all instruction will be strictly factory standards, with no allowance for innovation (hacking). That said: people have done what you are attempting. You should know that only the official BootCamp Assistant download will get you where you are going. While Apple does offer a page for BootCamp Support Downloads, even those cannot work unless you have that 1st official download from a licensed Mac.

noalula wrote:

 

I already did installed Windows without bootcamp.

I have no way to recover the OSX system.

Yes, you do.

1. Boot into Internet Recovery -  OS X: About OS X Recovery - Apple Support

2. Install OSX on an external volume - OS X: Installing OS X on an external volume - Apple Support. This does not work on non-Apple hardware.

3. Run BCA from the external disk and download Windows Support Software to a USB2 flash disk.

For Macs prior to 2014 you can download BC drivers manually to the Windows side using System requirements to install Windows on your Mac using Boot Camp - Apple Support . Later Macs require steps 1, 2 and 3.