So I recently upgraded my office computer's power supply, and now when I put all of the cables back, the computer fans (CPU, GPU, and exhaust fan) spin for a second when I hit the power button, but stop and nothing happens. However the power supply light is on. Pressing the power button again does nothing, until I unplug the power cord and put it back, which just makes the fans spin for a second. I've been stuck with this for a month and I'm getting real tired. Things I have done was completely replacing the CMOS battery, changing the RAM slot, and testing the power supplies with the paperclip thing and they both work (old and new). I have completely taken apart the computer but can't find the problem. The power supply is a 400 watt which should easily power the i3 7100 and gt 1030 in it. Please help.