The ASUS Prime A320M-K board emitted a white flash when you connected the 700W power supply.
The ASUS Prime A320M-K board emitted a white flash when you connected the 700W power supply.
It seems your board might have been faulty, requiring the new PSU to reveal the issue. Generally, such problems can be fatal for both the board and CPU. Could you share a photo of the "Sparkle" (electrical arc) on the board? There’s likely a damaged component visible.