Unlocking Bootloader of HTC One X on Windows 8.1 / Linux Ubuntu
Linux is absolutely the best way to do this sort of things. This is a thread on xda about how to set the development environment on Linux Ubuntu in particular http://forum.xda-developers.com/showthread.php?t=2302780 

Follow these steps and you'll have fastboot command set up to do the unlocking process. Plus you won't need any driver to let the system recognize the device.