If you ever come across a Presario 2700 that has lines running down the LCD and you hooked it up to an external monitor and the same thing is happening, check the video memory which is located in the underneath compartment that is near the regular memory. I had to re-seat it a few times in order for the lines to go away. I don’t know the exact cause but it seems to work. However, I’m still testing and it may very well be a bad video memory chip. If that is the case, just search Google for the part.