Hello
 I must first say I am a complete noob to GPUs and installing my own. I decided to take the plunge and buy a new GTX1070 FTW to replace my old 770. My installation was going along well until I got the infamous "please power down and connect the PCI-E cables for this graphics card" message. 
Again, please humor me because I am new to all of this. From what I can tell my 675W power supply was providing power to my 770 via a PCI-E 6+2 and a 6. The 1070 has 2x8 slots. It came with two Y adaptors, both with two 6s converging on an 8. 
 
No matter what configuration I come up with (connecting the 6+2 and the 6 directly, connecting the two 6's via one Y adaptor, connecting the two 6s via two Y adaptors etc), I cant seem to supply power to my 1070 FTW. Please help! And please feel free to talk to me like I'm a child as I definitely feel in over my head at the moment.

Ozymandsss
Hello
 I must first say I am a complete noob to GPUs and installing my own. I decided to take the plunge and buy a new GTX1070 FTW to replace my old 770. My installation was going along well until I got the infamous "please power down and connect the PCI-E cables for this graphics card" message. 
Again, please humor me because I am new to all of this. From what I can tell my 675W power supply was providing power to my 770 via a PCI-E 6+2 and a 6. The 1070 has 2x8 slots. It came with two Y adaptors, both with two 6s converging on an 8. 
 
No matter what configuration I come up with (connecting the 6+2 and the 6 directly, connecting the two 6's via one Y adaptor, connecting the two 6s via two Y adaptors etc), I cant seem to supply power to my 1070 FTW. Please help! And please feel free to talk to me like I'm a child as I definitely feel in over my head at the moment.

What is the power supply make and model?! A 6+2 and a 6 might boot the card but it probably wont let it do much else. Depending on the system you have the newer setups might even stop the system from booting without the correct plugs in but im not sure on that. Yes, use the 2 adapters that came with your card that take 2 6 pin pci-e lines and make them into a 8 pin. The reason why is because your pci-e slot on the motherboard supplies 75 watts, a 6 pin pci-e plug supplies 75 watts and a 8 pin pci-e plug supplies 150 watts. That's why you need two separate 6 pin pci-e lines for one adapter and two more separate 6 pin pci-e lines for the other adapter. Your psu, if its truly a 675 and a good model, should have that covered either with 4 6 pin pci-e lines or 2 6 pin pci-e lines and 2 8 pin pci-e lines. Please becareful though cause there are 8 pin EPS connectors, which are for extra power to the mobo itself, that look very similar to a pci-e 8 pin, but the 8 plastic holes in the plug are keyed differently between the two so you cant use the wrong line. Although, some people have been able to get them to go in the wrong connections by really forcing them like madmen,lol. So if its not going right in, then you probably have the wrong plug. Also, make sure when you plug them in that the little thumb lock/release on top of the plug is catching the other plug or it may not work right and create resistance and heat in the plug from a bad connection and you could end up with a meltdown.

Thank you for the input thus far. This is my PSU: 
 
So should I be able to go buy a second 6+2 PCIe cord and connect it up, thus having two 6+2s running from the PSU to the GPU?
I don't see any unused cables coming from my PSU presently so I suspect I have to buy one. The only other cable, as stated in the OP, is a 6.

Ozymandsss
Thank you for the input thus far. This is my PSU: 
 
So should I be able to go buy a second 6+2 PCIe cord and connect it up, thus having two 6+2s running from the PSU to the GPU?
I don't see any unused cables coming from my PSU presently so I suspect I have to buy one. The only other cable, as stated in the OP, is a 6.

You have to have 50 posts on the forum, and not spam....good posts to post links. So if you add a space or two somewhere in the link it will put it up so we can see. No, you cant buy a second "cord" to do that. If you have no other lines left then either your psu is a lower quality unit or its a very old unit from 10 years ago that usually didn't have more than two at that wattage back then. You can get a molex to 6 pin adapter, which is what used to come with the gpu's years ago. Maybe a friend might have one or you can buy one. It would look like this:  http://www.newegg.com/Product/Product.aspx?Item=N82E16812423173  then you can connect that 6 pin to the 2 6 pin to 8 pin splitter that you have now. That will give you the other 6 pin pci-e plug to go with the 6 pin pci-e plug you already have on the psu and then you can use the 6+2 pci-e pin coming from the psu itself and you should be good. My worry now is that your psu may not be a very good unit, but until you put a link up that we can see I don't know.