I think my PS, 2 years old went bad. Bout a new one corsair hx750i, unpluigged old, first thing I noticed, biggest plug is 9 pins long, old ps had a 9 pin slot but longest on new PS is 7 pins. MB is asrock extreme6. Help...
No. The psu is proprietary. All psus are, even models are different hookups at the psu. It's done on purpose to stop ppl adding extra cables where they aren't supposed to go.
You need to use the cables that came with the Corsair on the Corsair, you cannot use the cables that came with the Seasonic.
The only connectors you need worry about is the component end, not the psu end. If the Seasonic Focus Gold died after only 2 years, either its defective and is covered under warranty or there's an issue with the pc that caused a failure. Those units don't usually die in that length of time.