Whole screen is flickering in black lines, brand new PC, please help

[tenjk]

So, I've bought a new PC 3 days ago. These are the specs:

Windows 7 Ultimate 64bit
Sapphire HD7850 2GB OC
Intel i5-3750K
ASRock P67 Pro3
8GB single channel RAM

For the first two days, it worked. Two hours ago, however, my whole screen started flickering / flashing in these barely visible black lines. Is it the monitor that's dying (it's 5 years old)? How do I fix it, if it's not the monitor? It's very irritating.

I've already checked the cable, that isn't the problem.

 

[popatim]

its really difficult to check tell if its the monitor or the GPU with having another pc/laptop or monitor to test with. Either test your LCD with someones laptop or pc, or test your pc with another lcd is about the only way.

 

[tenjk]

I've just tested, still the same... I guess the problem is in the GPU, but how is that possible? It's like 3 days old.

 

[popatim]

Most out of box failures happen real soon after you start using it. The general rule is if it lasts a week it will last years (usuallY)

 

[Sceritz]

Hm Mine is doing the line and block thing as I type: http://www.tomshardware.com/answers/id-1711521/distorted-lines-blocks-brand-computer.html

I should probably just go head and get it replaced huh?