My Findings with Linux Ubuntu.
I tried Ubuntu Linux on the hard Drive with Vista.
Ubuntu used the Bug file for windows and made Vista second boot, Ubuntu first boot.
You have 30 seconds to use the up/down keys to choose which one of the two you want to boot up.
you will be given an option during loading as to how much space you want to give Xandros Presto on the Hard Drive for Linux for saving programs and files etc.
I blundered here and left to little for Vista.
If I were you check up on how to remove Xandros Presto before installing just in case.
One other thing if its on the bug file and you can delete Xandros Presto ok, you will find your pc still boots on the second boot screen when you only have Vista installed.
I never got rid of the second boot screen properly, I reduced the 30 seconds to 0 seconds and my pc now boots as it should.
Hope this helps