Hi Gharin,
Are you getting any error messages when the launcher window closes?
Also, I'm assuming you're using the same router now that you were using before when Silkroad was working, right? You shouldn't have to open ports in the router, but if you want to try that then go to
http://portforward.com/ for info on how to do this for most routers.
Have you taken a look at your hosts file? For XP users, it's located in the C:\Windows\system32\drivers\etc\ directory.
Did you install an antivirus or firewall program after your rebuild? If so, it may be preventing traffic to the servers. Be sure to let all of the applications in C:\Program Files\Silkroad\ have access.
Hope this helps, and hope to see you back online soon.