Dell Inspiron One 2320 All in one (Black Screen)

HI,
My Inspiron One 2320 powers up but shows nothing on the screen. Just black. I hooked up an external monitor and it works . Even the touch panel works with the main unit. I assumed the Lcd to be bad . Ordered a Lcd and replaced it. Turned on the computer and ,nothing. Same problem. So, I restored the computer to factory default and still nothing on the screen. If someone has had this problem please let me know what you had to do to correct this.
Thanks in advance
Alan