I had similar problem with Medion WIN 2140. The harddrive crashed, I bought a new drive and had to reinstall Windows from scratch since I had neither a backup or burned the reinstallation CD's. First I installed Windows7 and every driver/application/BIOS available from Medion's download site. At first my WIFI worked OK but somtime during the process og BIOS/driverupdate my WIFI antenna turned off. The antenna can be turned on/off with a easy access button (touchpad to the right of powerbutton) but WIFI button dows not work.
Medion's danish supporters told me that Windows7 is unsupported. So I had to reinstall using Vista. Still not able to turn on WIFI. I'm pretty sure that BIOS prior to version 1.0K (dated 06.01.2010) had a "ON" possibility but is now limited to "OFF" og "LAST STATE".
Medion support wouldn't og couldn't provide me a previous version of the BIOS. In fact Medion DK's support doesn't seem to know anything about their products.
However I have found the solution myself. Launch Manager application is needed for Easy Access buttons to work. Current version 126.96.36.199 of the application is faulty. In registry i found that pressed keys call the file fn.exe, this file is not a part of the OS, Launch Manager or any other Medion driver/application.
I googled for and found the prevoius version 1.4.9 of Launch Manager. This version works without any problems on both Vista and Windows7.
I wrote to Medion support to replace the faulty application on their support site. But with my current Medion experience i daught they will do anything about it. So instead I post this reply to help others.