A question about Setup detecting previous installs

[jaclaz]

Sorry if this is not the right place, but I guess that experts with Unattended are the most likely to know the answer.

When you boot from the 2K/XP CD on a PC that already has one (or more) installs, Setup "detects" them and offers the option to Repair them.

Question is, HOW is this detection performed?

I mean does it search for entries in BOOT.INI, looks for \Windows or \Winnt folders, searches the entire hard disk for some "tag" files or what else?

And another one, it is possible to install 2K/XP on a non-standard directory (i.e. not named \Windows or \Winnt) but must this directory be on ROOT of the drive or it can be a sub-directory, as an example \MywinXP\Windows ?

Thanks in advance for any and all ideas/suggestions.

jaclaz