power supply are you sure of this,when turn on is the fan inside is not blowing,it easy to replace psu,my power supply is 4 1/2 years before i replace,the price of this made in china more or less $30.00.the important on specification is capacity how many watts
your psu.check on www.psuebay.com
on frigure as sample disconnect psu besure power off and disconnect all connection at the back of cpu.open cover of psu
two quick lock in bolt loosen and slide off cover,
on psu there are multiple colors cable that are supplying your
mother board and others devices such as cd room,floopy anf hardisk, pull out or disconnect supply cable on mother board and other devices,then at the back side of cpu beside psu there are 5
screw loosen this and pull out your psu(power supply unit).then if you have new one just reverse the process of disconnecting psu on connecting back new one.
have anice day,rate me if your satisfied to my solution,thanks a lot.