Arduino Yun usb led doesnt light up

i have to use arduino yun for my project.It was working properly until i had to install some packages for node.js.Now the usb led doesnt light up.I uploaded the yunterminal sketch and realised that the uboot keep restarting and doesnt stop.any way to reset it? ive tried pressing all the reset buttons on the board.
Thank you

Can you post the YunSerialTerminal output?