Please note: I am not asking about prevention.

Let's suppose somebody gives you a PC that is loaded with malware, and
it's your job to fix it.

What is the fastest, easiest, way to go about it?

Is there any way to clean the machine without loading any new software
on it?

Would it be best way to clean the machine without booting the machine
from the infected drive? For example should the hdd be removed, and
connected to another PC as a second drive? Or, should you boot from a
CD, then have a networked computer actually clean the drive? And what
software woud you use to clean the infected drive? Can the process be
automated?

Thanks, in advance.