It has to have a minimum current draw on each 12V rail or it just turns
off. So if you're computer is not turning on, just add more stuff in
your case to consume power (lights, fans, hard drives, old hard drives,
whatever), and its best to put some power consuming device attached to
the first and last slot. (You need a minimum of 1 amp on each rail, the
mobo is rail 1, slots 1-3 (left to right looking straight at them) are
on rail 2, and slots 4-5 are on rail 3.) Then when you try to power on
the computer, it works! Hopefully it will stay that way.
Background:
I heard this PSU had a high failure rate when I bought the P150 case.
So before I put everything in the new case I hooked up the Neo HE to my
motherboard only to find out that the computer wouldn't turn on like
people were reporting. Then I researched, got the thing to work, and
put this info together for whoever finds it.
More info:
http://www.hardwareanalysis.com/content/topic/55019/
http://forums.silentpcreview.com/viewtopic.php?t=27863