Arrgggh.....A4000 PSU problem

[Jose]

Got my A4000 assembled but the thing doesn't power on. It does make a low, repeated noise on the PSU, wich is exactly the same if I turn it on without having it connected to the motherboard... and the fan doesn't start in either case.
Does it need to be connected to the motherboard for the PSU fan to work? Cause if it doesn't I might have a broken PSU.
If it does, what could be the cause?
There's a connector on the motherboard that says key, but I think that only blocks the mouse and keyboard if used right? I also didn't coonect the power led but I'm pretty sure it's irrelevant...
I runned out of ideas and don't wanna end up blowing off the thing so, any suggestions really appreciated.  

[Jose]

I've tried it without any drives connected too... Should start cause the motherboard and 3640 card would still be working, but the same happends....
 :-(

[Jose]

New info. I tried it also with just the flopy and the CDRom connected and the CD Rom light flashes along with those little kinda click sounds...
So I guess the motherboard is not at fault :-)
I still don't know what it is though  :-(

[Jose]

@JimS

You were probably right!
I started disconnecting all drives with the mobo connected and it was the floppy drive that was badly connected! When I had removed all the drives (HD and CDROM) I had forgot to disconnect the floppy too...

Cheers

[Jose]

By the way... this PSU, wich I think is pretty much a standard A4000 one, makes a lot of noise!! I was really disappointed...