Ports closed to incoming traffic

A few days ago out of the blue all incoming traffic from VUZE suddenly stopped. I can still upload, but cannot get anything inbound. I did some testing and I keep getting the same type of results stating that the port is closed. I have tried multiple ports and all have the same result. I thought at first it was Vuze-reinstalled, same result. Tried different ports (TCP/UDP), same result. I then thought maybe my ISP had throttled my connectivity but I haven't received any kind of notice so I doubt that's it.

This is my desktop station for downloads. It runs WIN Vista. Dual core processor, 4 GB RAM. 90 GB free space on the drive. It's been working without issue for years. I had just completed a download when the connection choked off. Strangely, I can still upload and navigate to any website. No viruses detected. Any help or suggestions would be appreciated..