Again? Jesus could learn something here, the PC was proclaimed dead more times that I can be arsed to count.
The PC isn't dead and it will never be. Why? Cuz it's the pinnacle of technology and as such it will always have it's devoted followers. Sure, phones, tablets, laptops are taking over a segment once reserved for PCs, but the PC keeps moving forward, always, relentless, while other mediums gets forgotten as time pass by.
The next BIG thing will be virtual reality and only the PC has the computing power to deliver the perfect experience.