The easiest way to unlock an htc bootloader is through the official htc dev site. The processes are simple. 

Requirements:

• A pc with network connection and android usb drivers installed. (click here to install the driver)
• Android tools. (Download android tools here)
• A usb cable (stable one) 
• Internet access

Let begin the unlocking process:

1. Type htcdev.Com in your browser

2. Click on unlock bootloader button 

3. Click on start now.

4. Type in your phones model no.

   And follow all the remaining steps..

     That is all... 

   note :

   Dont forget to register ur accnt.