Dreamlink SD Need Help

I have a Dreamlink SD no hdmi it has usb Iam having a problem turning the reciever on
I think I put the wrong file in the usb port,and now the on and off switch is acting up,
when you turn the system on green light appears on and then off, thats what happened,
I tried to put the correct files in the usb port not working, so maybe it will work though the serial port
thats why I need the files for serial port.maybe you have another way to fix my dreamlink sd
need your help.
I have the null cable