How to connect the wiring to the right connections in a M9040n When the power supply is connected to the mother board the power supply works and power stays running. when I connect all the other wires the power supply will not come on. Is this a motherboard problem or what else may be wrong.

It's a simple problem...... in most cases. 11 YEAR OLD PC
does the PSU fan spin, it must ! turned on. when it works?
in real shop we have spare PSU in the shelf there, omg it works or not?
we hot wire the PSU under suspicion. , the 1 jumper wire.

http://www.pcdied.com/power.html#Jumper

my guess is that works, the paper clip test I call it.

so you find hat all PSU have lots of wires, sure. looking inside.
the big wires matter, not the tiny if power turns on .

well, the big bundle goes to the mobo. 24 pins, (see jumper above)
the other cables run many things.

why not just try them one at a time to see which one is shorted?
easy no?, called fault isolation techniques.

pull floppy power, (i bet you dont have one)
pull all HDD, power.
pull DVD (cd) power, or BRD. power, blue ray?
if you have the VGA aux cable there,??? i cant see in your PC
then pull that next , doing so will kill the VGA card dead, or it goes mad.
so pull that VGA card (called an option addin card)
NVIDIA GeForce 8400 GS (and option DAY 1 new)
if yes, best i can tell it does not have the 6 pin AUX power
and means the card uses less than 75watts (flea power)

then pull all other PCI or express cards.

does the CPU fan spin, and is clean and heat sink clean?
the VGA card too can have fan is it dead, or packed in lint.
next pull ram, run no ram, the 1 stick at a time in bank 0
if all sticks work in bank 0 try all sticks, if you have 4 stick
add the 1 at a time.
see?

is the RTC coin cell battery fresh?. they most times never last 11 years, it needs changing first. if not BIOS goes NUTS.
all PCs over say 7 years, best to do that.

bios nuts,= PC nuts, and owners hair falls out.


now learn this,
lacking spare power supply PSU
diagnosis can be very very hard
what if the PSU you have is weak.?

• PSU come on the following forms.
• GOOD
• BAD/ dead. ( add huge list here, ask)
• weak (yes weak happens)
• overheats fan dead or packed full of lint after 11 years never cleaned.