In Windows device manager, does anything change when you connect the board? It will not be under the ports section, not quite sure what the section is called.
The TETRIX PRIZM uses a FTDI chip (according to its documentation that I found yesterday on the web) and hence is not a genuine Arduino. You might have to install the drivers (from memory, they should have been installed) or to update the drivers (download from the FTDI website, I do not have a link at the moment).