need help adding pololu a4988 to E1 makes ramps unable to connect (no replies)

i am using arduino MEGA 2560 with ramps 1.4 everything works fine until i put a a4988 on e0 for a second extruder. after it is inserted windows will not recognize it at all. like i never plugged in usb. if i take it out and plug in usb it will discover it and everything works fine again. i ordered another a4988 driver but does the same thing.

is there something i need to do before i put in the driver board?

thanks