as you should be able to see from this picture:
i have 2 PSUs. the 2nd one powers all my case fans, cathodes, and optical and floppy drives, and 7900gt.
there is a 120mm fan in the front of the case, that is powered from the motherboard.
if i have the 2nd PSU on, and the main one off, so all the fans are spinning, and the lights are off, this 120mm fan turns on... even though the PC is not on...
EDIT: did some more investigating.
the 120mm fan is powered when the 2nd psu is on, and the main psu is unplugged.
if the 2nd psu is off, and the main psu is on, the fans connected to the 2nd psu recieve power still.
if the 2nd psu is on, and the main psu is unplugged, the mobo power led is not lit up.
i think this has been happening ever since i got my 7900gt with the pci-e power connector, which runs off the second psu.
i really, really, dont get this. is power going through the GPU, to stuff the other side of the pci-e bus?
also, is this bad for my PC?