You may remember back in December Boxee announced that they were killing off their PC based version of the Boxee application and at the time they send it would be withdrawn at the end of January. So if you still want to get the PC version get on to Boxee.tv and download it before it gets pulled in the next couple of days. If you still want a PC media application checkout XBMC or Plex
At the time Boxee said:
We believe the future of TV will be driven by devices such as the Boxee Box, Connected TVs / Blu-Rays and 2nd screen devices such as tablets and phones. While there are still many users who have computers connected to their TVs, we believe this use case is likely to decline as users find better alternatives. People will continue to watch a lot of video on their computer, but it is more likely to be a laptop than a home-theater PC and probably through a browser rather than downloaded software.