hi i am having a few issues with my Dual core system, where when i press the power button everything except the fans start but only for a second before restarting, i can see the LED's in the optical drive and the PSU fan runs, but it wont even get into bios, am i right suspecting PSU? or is it something else, to be honest i have no clue
As you surmised earlier the next course is to try a different PSU. See if you can borrow one from another machine or a friend to test this hypothesis before simply buying one. If your machine still does not boot then there are many potential causes to investigate. Next try your PSU in another machine and see if it boots with your old PSU. If it does boot then it is likely your motherboard. If it does not boot then it could be the motherboard still as well as the PSU or a nagging short in the PWR switch or RST switch of your case. I found a client's machine with just that.