Inspiron 3521 Inverted Video

Greetings,

I have an Inspiron 15 3521 laptop and the display suddenly appears to be inverted (it looks like a photo negative). I know of no changes or strange events that occurred around the time this started. The laptop is JUST over a year old, so the warranty has conveniently expired. I tried to get support from Dell and the tech. said it sounded like the color calibration had gone bad. They said they could login and fix it for an "out of warranty" fee. Before I go that route, I was wondering if anyone here could give me the steps on how to fix that? Or if it might be something else?

Thank you in advance for any assistance. If any other information is needed, I'll gladly supply it.

Regards,

--- Gary