Try pressing firmly around the edges of the LCD whilst it is on and look for any change.
Also try twisting the screen from corner to corner (Gently or crack).
The LCD has contacts all the way across the top these are held with a metal frame and most are glued down with plastic and coper films, Ive found many screens to fault there.
Replacement screens can be ordered from Hong Kong via Ebay there cheep usually about $120au - $150au and i can vouch for these screens there flawless and warranty is upheld.
Good Luck
Also try twisting the screen from corner to corner (Gently or crack).
The LCD has contacts all the way across the top these are held with a metal frame and most are glued down with plastic and coper films, Ive found many screens to fault there.
Replacement screens can be ordered from Hong Kong via Ebay there cheep usually about $120au - $150au and i can vouch for these screens there flawless and warranty is upheld.
Good Luck