I currently have an Ubuntu laptop and external hard disk installation. I would like to know if it is possible to use these full installs, after a bit of configuration, to be used as installers to create new installations on others' computers without copying my configuration or passwords, and without affecting my system during the installation. That is, I want to create new installations, without changing my configuration to that of the new system, and having those installations be very similar to those created by the ones created by regular media.
Sorry if unclear or mistagged, and feel free to edit.
Edit: Also, remastersys does not work for me and this is not a duplicate: I need to install from booting my full installation on another system and then installing from there, not making another Live CD, which I am trying to avoid.
Edit: I am doing this to have a better demo system that works fully, and does not suffer the issues of a live CD. I'd preferably install from there...
Is this any help? http://www.arsgeek.com/2006/09/19/ubuntu-tricks-how-to-generate-a-list-of-installed-packages-and-use-it-to-reinstall-packages/. What it explains is how to get Ubuntu on your laptop too give you a file listing what's installed, and then to use that list on another PC to install the exact same software. I may have misunderstood your question though! Update: this example might be even easier using the tool APTonCD: http://www.ubuntugeek.com/create-backup-of-all-installed-packages-using-aptoncd-in-ubuntu.html
Update 8th May: If I understand then, you have Ubuntu installed on the external hard disc of your laptop, and you want to tote this around to your friends and install Ubuntu from the portable HDD on to their PCs.
I found a simple way to do this... I had a chroot'ed copy of the live CD filesystem(From the squashfs) and by using ubiquity in the fake root, I have installed to other target systems. Also, a short shell script helps automate entering the fake-root and running ubiquity. The main thing to avoid is accidentally overwriting your old install on the external HDD.