I am putting together a build using the LifeHacker specs and cannot get my build to start. The issue seems to be with the power supply.

When I turn it on with only the main power supply connected from the box, everything starts and I get an error in which the monitor cannot get a signal. When I connect the additional 8 pin power supply...nothing. The build will try to start, but stops after less than a second.

What am I doing wrong?