Advice needed on pc build, no beeps/screen/keyboard, fans working

aloevera

Commendable
Dec 14, 2016
2
0
1,510
Hi everyone, at the end of my tether here and looking for some advice.

This is my first computer build, and I've put it all together using online tutorials and the manual from the motherboard. These are the parts I used, some new, some open box from amazon.

AMD FX-4300 3.8GHz Quad-Core Processor (open box)
MSI 970 GAMING motherboard (open box)
Corsair Vengeance LP 16GB (2 x 8GB) DDR3-1600 Memory (open box)
Zotac GeForce GT 730 2GB Video Card (new)
Crucial MX300 525GB 2.5" Solid State Drive (new)
Antec NSK4100 ATX Mid Tower Case (open box)
Corsair Builder 600W 80+ Bronze Certified ATX Power Supply (new)

According to partpicker they should be ok compatibility-wise.

The cpu fan, case fan and psu fan spin and the motherboard lights and lights on front of the case work, but nothing else happens. no light on the keyboard, nothing happening on the screen. No beeps, even after I figured out where to put the beeper :p
I've triple checked all the connections, tried without ram, with 1 stick of ram, without anything else plugged in except the cpu... nothing changes. I've also tried to clear the CMOS by touching a screwdriver to the JBAT1 pins.

I wonder if anyone has any other suggestions, or could tell me which part would be best to replace first?
I've never had open box stuff from Amazon so I'm not sure if they would try to resell stuff other people have returned as faulty?
Also, the case didn't come with enough brass standoffs for the motherboard, but I put the ones I had in strategically so that the mb would be stable... would that make a difference?
Thanks in advance :)