SMPS problem?

hi there,
what about changing your power supply at cpu,disconnect the avr before doing this,disconnect all terminals leads on pc board,cd room and hardisk if you have spare of
power supply or other pc,you can installed to check before buy one,if still shut down whiile power supply was replaced,replace cmos battery,check also your video card and memory card,you can run your windows with out hardisk and cd room just to check if your system is running functionaly.regards

the problem is with yur smps i think.yur turn on button is directly connected with the smps i think.if the smps fails to run yur system will hang.please wipe and dust yur smps completely and see if the system is working.. or else you should change yur SMPS..