Just got through building another computer. Everything is plugged in correctly and I hit the power button only to see the cpu fan spin up for half a second and then stop. I rechecked all of my connections and after a while of trying to boot with different things unplugged, I discovered having the sata power cable plugged into either my HDD or disc drive caused it to shut off right after starting.
I tried booting with neither the hdd or disc drive plugged in and it booted fine. However, connecting either of them caused the problem again. I tried different sata power cables and none of them worked. The hdd is brand new and the disc drive came out of a computer that I know it was working in. I also took the psu out of a working computer this morning. Any idea what my trouble could be?