My desktop computer continued to deteriorate this weekend. Not only could I not maintain an RDP connection into the desktop, I also started having problems synching my phone, copying files across the network, and general performance problems.
On a hunch, I disabled Windows Firewall and all these problems disappeared. Since I am behind a hardware firewall, I'm not concerned about the security implications.
Not sure why this happened – but the firewall rules on this machine numbered over 400 in the private profile (Start -> Search for firewall advanced). Other machines I've checked have ~200 rules.
Perhaps the software firewall was overloaded...