Laptop screen partly discolored vertically

I was exchanging my hard drive and when i rebooted my laptop, part of the screen had a different lighter color. Putting the old hard drive back did not solve the problem, so i started assuming it was caused by hardware failure. I opened up the laptop, checked every single connector and made sure they were all attached correctly, but the screen is still discolored. What could be the cause of this problem and how can i repair it?

http://i.imgur.com/DMAukNV.jpg

The make of the laptop is Medion Akoya MD 99076 (P7816) Graphics card: GT 645M Processor: i5-3210M 8GB RAM, 256gb SSD And it is running windows 10.