Due to encryption on my corporate laptop I opted to install Ubuntu 9.10 on a flash drive and just use it as my hard drive. I tried the vmware but it crashed my xp a couple of times. Now I have a couple of concerns since I am totally new to Ubuntu and Linux.

First, would it be possible for me to transfer my installation to a new usb drive? I now have a 4gb and it may get filled up soon, I don't seem to be able to see my actual files when I browse the usb drive. I also tried copying all files from this usb to another and boot from it but that failed.

Second, whenever the system boots up I am never prompted for a password, it is always the username ubuntu. Which I guess means if I lose my usb drive my data is open wide. Is there a way to secure it or to use users and groups as on a regular hard drive installation?

As a background, I created this by going into a working Ubuntu installation, System -> Administration -> USB Starter Disk Creator (was that the right way to start with?)

Thanks!