When you first power your new system up.
If all the fans spin but you get no post from the bios of the motherboard, by an audible set of posting beep codes or if the board has a two digit lcd error display on the motherboard.
And you also get no power to any usb ports, or get any video signal output from the video ports of the motherboard.
It can mean that you forgot to plugin the eight pin E-atx 12v power block from your power supply unit to the motherboard.
In a vast majority of cases.
Because the eight pin block on the motherboard is often put in a place on the motherboard that can be hidden by VRM heat sinks for the motherboard and alike.
I have linked a picture to the power block mentioned, click on the second picture of the board in the link.
You can see it to the right of the motherboard just above the top VRM heat sink of the motherboard in black.
If you have not already connected this then the board should work and post once it is connected.
http://www.msi.com/product/motherboard/Z97S-SLI-Krait-Edition.html#hero-overview
If the board has a 15pin Vga Dsub, Dvi Video output you must connect your monitor to this first of all.
You will need to then enter the bios of the motherboard, if you have a Pci-e based graphics card placed in the Pci-e slot of the motherboard.
Change the default graphics display to initialize first to Pci-e or Peg mode via the bios menu options, save the settings in the bios before you exit it.
Then swap the video cable from the back of the motherboard to any video output port of the Pci-e based graphics card.