Problem with shutting down

Hello, I am having a problem with my computer shutting down. Whenever I try to shut down, everything goes normally until the part where the computer components stop receiving power. All the fans keep humming along and the lights stay lit, and never shut down unless I hold the power button for 5 seconds or so. My monitor shuts down after going through the displays that are normally shown in the shut down process.

I tried disabling all startup processes, thinking that something was causing a hang, but the problem persisted.

I recently installed new components: a CPU, CPU heatsink, and video cards.

I appreciate any help that anyone can provide.