I'm a novice at this stuff -- thanks in advance for your patience.
I just upgraded the CPU on my MSI A68HM-E33 V2 motherboard from an AMD A4 6300 to an A10-7870K. While performing the upgrade, I disconnected the side-mounted (exhaust?) case fan for the first time in order to get the side panel of the tower out of my way. After the upgrade, the CPU and CPU fan are both working fine, but both of the case fans are suddenly not working! The LED on the side fan is not lighting either.
I've triple-checked the (4-pin) molex cable that I disconnected and it seems secure. What are the possible explanations as to why both case fans stopped working?
I only have a 400W PSU, but my understanding is that case fans aren't usually a power supply concern.