Have a Crossfire formula IV motherboard with AMD Phenom II chip. Shut the computer down the other day via windows but then computer would not power back on. Found the power supply to be dead (no dc voltage coming out) Bought a new corsair at bestbuy. and put in. Motherbaord lights up (only the light by the power supply) but nothing else. No beep, no fan nor harddrive movement. Best buy suggested it was the motherbaord but since so old, I had to purchase from overseas. Came today, Put in - same thing. Eventually foudn the new power supply 8 pin cable ALSO had no voltage on it. Going to exchange tomorrow (hopefully) but the question is did the old motherbaord, or CPU chip, kill the new power supply, or just coicidence that the new power supply wasn;t fully working out of the box? And if I put a 3rd new power supply in (which I will test the voltage before connecting) and it dies too - then what is going on??