PC build problems - several questions (newbie)

I got in all my parts and began building today. I think I finally finished, but ran into problems. First, my monitor cable isn't compatible with my GTX 1070. The end of the monitor cable is too small, but even when I connect it to a larger one that fits the size of the card, it won't go on there. How do I know what to buy to make this work?
Second, I tried putting my GTX 660 ti back in there, but when I start up the PC, all I get is "PLEASE POWER DOWN AND CONNECT THE PCIe POWER CABLE(S) FOR THIS GRAPHICS CARD". I don't know what PCIe Power Cables are, so that doesn't help much.
Third, the back fan isn't compatible with my motherboard (building it inside the case of my old PC, and kept the fan in there). It has 3 pins on the conector, while the motherboard requires 4. How do I know what fan I need to buy and make sure it fits in my PC's case (mid-size)?

I need help, lol.

Dude said:

The card will have DVI port, an HDMI port, and Display port. You will need the cable that your monitor uses. As far as PCIe Power cables, that would be the 6pin, and 8 pin connector from your PSU

What do you mean by I'll need the cable that my monitor uses?
Oh, okay. But I think the PCIe only goes into half of the slots of my GPU, it does have an extra small set, but doesn't fit. It won't matter if I can get my monitor connected to the GTX 1070, though.

TairikuOkami said:

1, What type of monitor you have? I guess you have VGA connector as on the picture?



2, you should have 6 pin and 6+2 pin, which you can use Nvidia Gtx 660 ti Unboxing and Install

3, 3 pin fan can be connected to 4 pin, the 4-th pin just provides the ability to control fan speed.

1. Yes, that's the one I got, but the GTX 1070 requires a larger one. I do have a connector that can be linked with my monitor, which fits the size of the GPU, but it won't go because the connector has a few extra pins.

2. Yes, I got the 6+2, but the +2 thingy won't fit, but I'll check again.

3. Oh, right. I guess that's one solved. :)

TairikuOkami said:

1, You need to buy VGA to DVI Adapter [HD] - YouTube (costs about $5)

VGA to DVI is the one I need 100%? Because I currently have something that looks like it, but won't fit, or is that named something else? I don't want to buy the wrong thing.

TairikuOkami said:

As mentioned before, GTX 1070 has DVI, HDMI and Display Port, so if the monitor does not fit, it can be only VGA.



If you go to the shop and explain the situation, I am sure they will give you the proper one, so I am 100% sure.

I just did a bit of research and think I need a VGA to DVI-D adapter, since that one doesn't have the extra pins that prevent the one I'm using now from connecting.