Hey mmbrown,
Usually that is a sign that something has blocked your ports on you. Unfortunately it happens sometimes that a change, or power outage or even Windows Updates can change this on you so checking those first are the way to go.
On the router settings did you also verify that your internal IP of that machine had not been reassigned or changed by the router.
Go to Start > Run > type 'cmd'
Then in the DOS box type 'ipconfig'
This will give you the IP Address of that machine, then open the router and verify that you have that has not changed.
Make sure if your XP firewall was disabled before that is still disabled, with updates it has a habit of turning itself on without you knowing it.
Also do you have Norton Antivirus 2005, this with some updates may also reblock WinMX and it may have to be re-Allowed in the Worm Protection.
I am curious if you have checked all of these and still had this trouble what other changes may have taken place to cause this...
Your not the first person that has had the secondary connections become erratic on them..meaning that they fluctuate between normal to low numbers..
Let me know please...
