Here is quick guide of installing MTK6577 Usb drivers on PC Windows 7 x32 or x64 , MTK chip is also used in China Mobiles. I will provide you Guide for installation and Download for these drivers. As we know MediaTek uses VCOM Driver for fastboot and flashing china mobiles. This tested by SP Flash Tool.
Requirements : Download VCOM USB Driver for MTK 6577 China Mobiles.
Follow these steps.
Note : If you not seeing this try removing battery from mobile and plug into computer without battery.
Note : This will only appear in Windows 7 are later.