Video card problem

I bought my zotac gtx 760 dual fan from my friend. It was working fine in the past 1 month. but after 2-3 months the screen pixels appearing suddenly which requires to force restart my PC. Sometimes I just wait it up and it will suddenly disappear without restarting but my game will crash...

So about a month ago I finally built a new PC after about 5+ years on my last build. Everything went well and I had been using it happily for about a month (literally will be a month tomorrow). That is until last night, when I rebooted the PC and upon booting the monitor just sat there saying...

As you can see in the pictures, my screen is malfunctioning. https://www.dropbox.com/s/tfsn5fs5625eqap/IMG_20160313_111233.jpg?dl=0 about a second after i press the power button. https://www.dropbox.com/s/xf1urkro54hs76l/IMG_20160313_111320.jpg?dl=0 my windows desktop after boot. It also won't...