It should be Tahoma or MS Sans Serif?
But it seems like it has a different size.
What resolution are you using?
Is it a LCD screen?
If yes, is it the "native" resolution of the LCD?
Are you using (in screen properties) "normal" size of characters?
Try posting an image with the menu and the word "ProDokugramEinstungen"

in several font sizes.

Check this, also:
http://www.neowin.net/forum/index.php?showtopic=318903QUOTE
Go to Start -> Run, then type regedit to open the registry editor. Now navigate to:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\FontSubstitutes
Now double click on "MS Shell Dlg" and put in the font style you want as the value.
Then double click on "MS Shell Dlg 2" and again put in the font style you want as the value.
After you are finished, restart your pc.
jaclaz