Duplicate screen issues/?

I'm running a Lenovo IdeaPad Y510P and ever since yesterday I have had issues with it showing duplicate screens. I use an LED TV as a monitor, and use and HDMI cable to connect it to my laptop. But yesterday there was a thunderstorm and after one of the lightning shots, the TV or the laptop just don't work together. I checked if it's the wire, i checked if it's the TV, i made sure the duplicate screens option is on, I restarte my laptop, took out the battery at times. I updated my system, and I even used system recovery for earlier that day when it was working. But right now it's just a black screen that says "No Signal". I tried other laptops and/or cable boxes and they work just fine so it must be the laptop or the HDMI port in general. I checked the system and it says that NVIDIA GeForce gt 750m isn't working properly. I think this may be the root of the problem but i don't know how to fix it. This has never happened before.I've never had problems with my laptop and TV screen in terms of duplication.

Hdmi cable are very sensitive to electromagnetic fields, as mentioned by you there was a lightning shot that might have damaged the cable… I advise you to check with a spare hdmi cable. Ask your friend for checking purpose only and if new cable works then it's time to replace the hdmi