Help with CPU replacement

Nada, power off, unplug. Remove the heatsink, remove the old CPU. Put in the new CPU, and mount the new heatsink. Plug in, then boot. done.

I'd add a few more precautions:

Make sure your BIOS is up to date and supports the CPU. ECS is sort of shady and this is an OEM mobo with little motivation for them to keep the BIOS properly up to date. Even if it doesn't it will probably still work, just give you an unknown CPU message and might make you manually set FSB and multiplier settings.

I've occasionally had issues with the OS not liking a hardware change but you just need to put those fires out when you come to it. This might be an issue if you go from a single core to a dual core. The only thing you can do in advance is make sure your OS is up to date.

Backing up your PC is always a good plan when you fiddle with your hardware.