ASUS FE171CG Can't access droidboot

Hello guys!
first sorry for my bad english

I downgrade my fe171cg from android 5 to 4.4 .
Now i am boot loop

When i try to access droidboot the usb symbol shows and turn off.but if usb cable connected dont turn off .

windows detect a CloverviewPlus Device but i cant work with xFSTK .gives error : windriver error 0x20000015
But i installed drivers correctly
Tablet dont boot up and i cant access droidboot .
if i have droidboot i can flash this but ....

Please help me !!!

and i haven't got recovery to use sideload