I have a presario 700z ,the machine boots fine I think, what I mean is I hear it but I don't see it..I swapped out a working good screen and still same problem.. is there a video chip somwhere or is the whole mother board fried??

did I mention it does work with a monitor plugged into it...anyone??

could be a chip failiure but doubtful as you've stated that the machine works if you hook up an external monitor.

it could be a backlight has gone (tell this be shining a bright torch onto the screen and seeing if theres outlines of a dialogue box etc)

it could also be that the thin flat wire that goes from the board into the screen has become damaged or isn't plugged in right. be careful if doing it yourself and to be frank i'd get a professional to look at it for you.

Thanks Janey, but Like I said I switched with a known working on, also put the one in question on a working machine ..works fine..I also switched all the small cables running to motherboard..and that's what confuses me the most is that the unit works great when plugged into an external monitor ......any other suggestions??

Check the BIOS settings to make sure the LCD is enabled. Also try the Fn key combination to switch from LCD to external display (might be a combination like Fn + F5 or Fn + F8). If it still doesn't work, check the LCD close switch to make sure it is functioning.

HEY buggz !!! you the man!!! It was the lid switch....I knew I could get help here..I don't know much about laptops, but I'm learning all the liitle tricks from all the knowledgable peeps here...thanks all that helped :cool: