Originally Posted by Fordun
Update - i took out the corsair and put in the old psu to see if it would still work...It doesnt but this does mean that my Cosair is fine but someone else is messed up.
It only means insufficient facts existed to know anything useful.
For starters, you should have known this. A defective supply may still boot a computer. A perfectly good supply can be defective in an otherwise perfectly good system. And defective computer hardware can make some otherwise perfectly good power supplies appear to be defective. In short, informed techs do not swap parts to learn what is defective.
Your replies will only be as useful as facts that you first provide. That means, for example, numbers. To have a reply without wild speculation means you must first 'see' something that can be posted. Voltages. Never see voltages without a multimeter (sold only in stores where geniuses are allowed to shop (ie Kmart, Wal-Mart, Radio Shack, Lowes). And extremely expensive ($17 in Wal-Mart; $4 in Harbor Freight). Without a multimeter, then facts necessary for a useful answer are no posted.
One minute of labor. Measure (on the 20 VDC scale) voltages on a green, gray, and purple wire both before and when the power switch is pressed. Report those numbers here to have an answer based in facts. Then boot the machine. Have it drawing maximum power from all peripherals. That means no Prime95. That means multitasking. Searching each drive, while reading a CD-Rom, while downloading from the Internet, while powering from a USB device, while playing sound loudly, while moving the mouse, while ... now measure the voltages on any one red, orange, or yellow wires. And report those numbers to three significant digits. Or if the system does not power, then report the behavior of each voltage as the power switch is pressed.
Do same for a 250 Corsair and for the new supply.
Once numbers are provided, then the few who actually know how computers work will report what is wrong. Without speculation. And also explain how a computer works on power up. No numbers means no useful reply is possible (which is true for more than just computers).