galaxy s4 screen flicker and dies

Ive had a galaxy s4 about 7 months...bought it on fleabay.....all has been well with it.... today i woke up and the screen was frozen..no button presses were working..i let it timeout and then it was fine... a few seconds later the screen started flickering like bright green and bright white...then went black..... ive tried pulling the battery and sim a few times but still no joy...

i can hear all the text notifications coming through, i just cant see them on the screen...


any ideas how to fix this????