fluxalex wrote:Hi again,
... Is there a way without having to install the system again, having to download the updates and additional software that I installed and configuring everything again?...
Yes, kinda, but it's rather cumbersome and pretty much noone recommends it. The best way is to reinstall the system, but (if it exists on the fulxbox version) you can use apt-on-cd to store all of your updates so they don't have to be re-downloaded.
Almost all configuration is in your /home/<user>/ directory, and most of it can be copied directly onto a new system, when I update, I just keep all of my /home stuff (by putting it on a seperate partition) however you should be able to copy files w/o notable problems. The terminal command "ls -al" will list all files in a directory (so open a terminal, cd to ~/ which is home, and ls -al) however you'll have to use "show hidden files" in your file manager to do that using a graphic enviornment's tool. I hope that makes sense.
fluxalex wrote:Basically what I'd have to do is to create an ext4 and swap partition on "sda". Then copy the complete root file system from "sdb" to "sda". Then somehow I'd have to generate a new "fstab" and reinstall/reconfigure "grub" so that it points to "sda" instead of "sdb".
Has anyone done such a thing already?
Yes, that has been done, exactly as you say, but I felt the need to repeat that I, and most that I talk to, don't do that and call it a "bad idea".
If you don't understand something, ask, I'll be sure to check back.