12 volt mb plug?

what does the 12 volt plug from the power supply to the motherboard near the cpu has to do with anything? when i plug the 12v in it runs a few seconds then shuts off?when i don't plug it in,it runs.... jugular5

Your question is very unclear and difficult to understand. If you have a P4 system, there is a 4 pin connection on the mobo in addition to the normal 20 pin atx connection. The 4 pin connection supplies additional power for the cpu.

sorry karsh44,this is a continuence of the "no power, no post"thread...but now ive run in to a new problem!my specs are:new gagibyte ga-7n400 pro2 MB
:new amd xp 2500+ with new thermaltake volcano9
:new PMI dual channel ddr {slots 1+3}
:used 400w psu
:new ATI RADEON 9200se 4/8x
i put eveything together like the MB manual says,with the last being the power switch and the 3pin power led,plugged the power cord in,press the start button,and the fan started and then died within 5 seconds...waited a few minutes,tried again,nothing happened,disconnected the power supply,disconnected the 12v mb supply,connected the power again without the 12volt,and it started up,but i shut down,because i don't know if it supposed to be running without the 12 volt connection!!this is strange?

any suggestion??? jugular5