New build crashes when I plug in USB

Hi folks,

I am in the process of putting together a new build and I seem to have hit a wall. The first time I put it together, I wasn't able to get it to POST; instead, when I hit the power button the fans would spin for a moment and the case lights would flash, then nothing. The MOBO system speaker made no beeps or noises whatsoever. I proceeded to disassemble the PC and breadboard it in order to eliminate the possibility of a short. Lo and behold, it POSTed flawlessly! Pleased, I built it all back up again inside the case and POSTed on the first try.

However, when I began installing the OS, I tried to plug something into one of the USB ports on the front of my Antec 900 case. This caused the PC to crash instantly. When I tried to boot, I ran into exactly the same behavior that I saw before: a quick spin of the fans and flash of the case lights, then nothing. Again, no beeps from the system speaker.

What is going on here? Is this an issue with the case (perhaps poor grounding of the front panel?), or does this have something to do with the motherboard?

For your perusal, my hardware is below:

Motherboard: ASUS M4A88TD-V EVO/USB3
CPU: AMD Phenom II X4 965
Memory: G.Skill DDR3-1600 PC3-12800 4096MBx2
Power: Corsair TX650W Power Supply
GPU: Sapphire Radeon HD6870 1GB GDDR5 PCI-E
Case: Antec 900