Built in screen turning on but no display

I also tried the lcd check pwr+d the colors r showing fine 

You can try checking the cable that connects the display to the mainboard for damage, but just about anything beyond that means a GPU failure -- i.e., replacement mainboard).  And yes, GPUs can fail in such a way that the external screen works when the internal one does not.

If it comes to that, consider the value of the system at this point (well under $100) vs. the cost of a replacement board.  It'll almost certainly be less expensive to replace the system -- you can find one a few years newer for less than what a board for this one will cost.