My power supply stopped working recently so I replaced it. Previously the pc would turn on immediately after the power supply was switched on and all fans would spin except for the gpu fans, which would struggle to spin for a short time and then stop for a while before trying again, so I thought it wasn't getting enough power. But now with the new psu the pc won't start at all. I've ruled out the new psu being faulty with the paperclip test and the motherboard is definitely receiving power as indicated by my keyboard leds turning on. I've also checked all my connections and reseated everything several times. I even reset the bios and have tried shorting the pins for the power sw to force the computer to start, could my front panel connectors on the motherboard be broken?
Motherboard: GIGABYTE GA-990FXA-UD3 R5 (rev. 1.0) AM3+/AM3 AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Motherboard
PSU: EVGA SuperNOVA 850 B2 80+ BRONZE, 850W
GPU: EVGA GeForce GTX 970 4GB SC GAMING ACX 2.0
Motherboard: GIGABYTE GA-990FXA-UD3 R5 (rev. 1.0) AM3+/AM3 AMD 990FX SATA 6Gb/s USB 3.0 ATX AMD Motherboard
PSU: EVGA SuperNOVA 850 B2 80+ BRONZE, 850W
GPU: EVGA GeForce GTX 970 4GB SC GAMING ACX 2.0