1. You probably didn't format the drive when reinstalling Windows... if not, try it.
2. It might help to install the game from a different source (disc).
3. If you've been constantly connecting with the same computers, the problem might be with them... try connecting the game with other computers.
I had a similar situation - there were viruses on another computer, and it seems they were blocking the LAN game.
P.S. Check your computer for viruses :smile01: