Hi, new to the forum. I had the same problem that many of you seem to be having since installing SP2 on my system. I found this site. The site offers many suggestions for optimizing the performance of your system including a fix for the connection problems we are all having. Scroll down until you find "SP2 TCP Slowdown Fix"

Down load and install the fix, I went from no connection to consistently Turbocharged without opening any extra ports, or changing any SP2 Firewall settings at all except unblocking Limewire when prompted.