RE: My DELL XPS 15Z screen issue.
Lower your refresh rate. When I installed Windows 8.1 OEM version on my Dell XPS 15z laptop I was getting a fuzzy screen. Like the screen was malfunctioning. I was about to revert back to Windows 7 when I lower my refresh rate from 60 to 40 and it WORKED. You don't know how happy I was.
So Bhakti try that and see what happens.