Are the SATA cables the ones that connect to the CD thing? I think I put those in right.
Yes they are but you also have one for your HDD make sure it's in also. And your SATA power cables are connected to each (hard drive and optical drive)
I think maybe the wires near the power supply would be messed up, because everything was running fine when I was using the old power supply (I needed a better power supply to get the full power from the card).
Maybe I forgot to connect something?
Here's a picture of your mobo sideways from how you see it in your case - I will refer to the points in the picture (and explain where you will find it/them)https://www.tekwind.co.jp/resources/products/8414_358456f7d9b234d4f85c40078afc96bebc1c0477.jpg
Your 20+4 (or 24) pin gets placed in the light blue 24 pin connector at the bottom of the picture (on the right of your mobo as look at it)
Your 4 pin (you may have a 4+4 pin - just use one of them) goes into the light blue 4 pin connector above and to the right of the CPU (above and to the left as you look at it)
one each SATA power to optical drive, and hard drive (from PSU)
one each SATA cable from mobo lower left in picture (lower right as you look at it) the Dark Blue in the corner to your hard drive, light blue for your optical drive (I don't think which one you use matters for the optical drive but...)
Hopefully you got all those in and they are secure
Don't forget your 6 pin into the graphics card.
Then everything should work (fingers crossed)