It turned out to be super easy
- download Elementary OS Luna and create a CD ROM from the downloaded ISO by using OS X’s Disk Utility (Luna is based on Ubuntu 12.04 LTS (“Precise Pangolin”)
- press F2 at the Medion and let it boot from the CD, then install Luna right away
- follow the instructions at ubuntuforums.org ( now askubuntu.com ) to install the wireless driver
- go to to the admin panel, replace the Luna browser with Chrome, get Light-zone and add also Libre Office. Several more changes are also recommended.
I guarantee you a brand new machine 1 hour later that will boot in less than 30s, sleep in another 3s, start Chrome in <1s and render a Facebook page in 1s. Incredible. Something Microsoft was dreaming of for decades. Microsoft even wants us to trash these old XP machines by ending any support. That would be another incredible waste as look and feel with Luna is better than ever.