Oh Boy! You may be opening a can of worms here...
There are nearly as many versions of this as there are board members. Did you catch Jens' rendition?

Actually it is in the FAQ.
Bryce's Kixtart Starter's Guide

I'm not a fan of copying the files on every logon. I use MCA's iexpress packages but cannot rely on his kix402.ok cookie. I found that even if the package failed, the cookie was dropped. Now I do:

IF NOT EXIST %windir%\kix32.exe GOTO 95_UPDATE
_________________________
Give a man a fish and he will be back for more. Slap him with a fish and he will go away forever.