What leads you to believe that the number of Active Opens are an issue? I would consider watching netstat (or Sysinternals tcpview) to watch network connections to see if some application is opening unexpected network connections.
I would suspect that there is something else slowing down your computer. There is possibly an application with a memory leak. Network protocol stats would not show something like that. Maybe run perfmon for a period of time and see if you see any trending in some stats like available memory or CPU utilization.