This upgrade is so easy. Just do it. Even your dad could do this.

After the upgrade to a 320 GB 7200 rpm, the MacBook (1.83 GHz Intel Core Duo A1181, with 2 GB of ram) works like a new computer. However, the fan comes on so easy - and stays on forever. Is this due to the increased speed of the hard drive? Is there a way to turn down the hard drive speed when used on AC power?

I agree with several others here. It is not necessary and not recommended to perform the step 14-unpluggings. Everything worked fine without doing this step.