There was already a posting concerning this problem (
MediaBox broke my browsers. How to uninstall?, last modified on 31.07.12, https://groups.google.com/forum/?fromgroups=#!topic/media-box/NCaTU3DrtmI). The solution recommeded by a user was to ceate a new user account.
But this is of course no solution. A temporary solution is to delete the Winsock provider entries made by MediaBox. This can be achieved by resetting the winsock catalog with the command
netsh winsock reset
in a cmd window. You have to restart the computer afterwards. But you should be aware that this resets the complete Winsock catalog including entries of other software. The utility autoruns by Mark Russinovich (
http://technet.microsoft.com/de-de/sysinternals/bb963902.aspx) shows you all entries in the tab "Winsock Providers" so that you get an idea what programs you have to reinstall afterwards perhaps. You don't need care about the many Microsoft entries because all entries needed for internet work are reinstalled during the restart.
But the real solution is of course to fix the programming of the Winsock entries of MediaBox. Will the programmer do this? I want to mention that the blocking of the internet access occurs only with IE9 on my computer. FF works correctly. I am using Windows 7 Professional 32 bit with all updates applied.