>Start at the top: Which is my IRC client? Do not attempt to install anything on my machine, please; just info.

MS Chat is an IRC client. So is mIRC. Those are the two most popular for the Windows OS.
BitchX and IRC II (Epic) are the two most popular for Unix (Linux).

MS Chat is free with Windows. mIRC is commercial, unless you are using Sparrow, which is mIRC with some extra scripts, then it is free.

j