If you are using a Gigabit Ethernet Switch for connecting your Vista based computers to your home group then you might have problems in troubleshooting Windows Media Center Extender errors. You might notice poor video quality or slow performance or Video might not play at all. These issues happen only when  the PC is connected to the Homegroup using the Gigabit Ethernet Switch and the consumer grade switches. The problem occurs because of the small size of the buffer which goes insufficient. Since media streaming done by media center extender results in  a large amount of traffic over the switch, the buffer in the switch overflows and results in poor video quality and slow performance. This happens because the switch operates at 1000 Mbps speed and the Ethernet card in the PC operates at 100 Mbps speed. In order to manage the transfer the Gigabit switch has to buffer in between the switches, which may at time result in data over flow. Data overflow may also occur if the flow control is disabled

To manually enable the flow of control in Windows Vista computers click on the Start button and then open the Run box. In the Run box type NPCA.CPL and press enter. You might be prompted for Administrators password so please provide the password or just change the privileges accordingly.

Now Right Click on the Gigabit network connection icon listed in the LAN connections section and from the context menu select Properties. In the Properties Window click on the tab titled Networking.  In the Networking tab click on Configure. Another Window will appear and then click on Advanced tab. In the Advanced tab click on the Flow Control property from the Property box. When you select the Flow Control Property you will get a Value drop-down menu. In this drop down select the value that enables flow control in the Tx and Rx Directions and then close the Windows by clicking on OK. At times the issue might not get resolved by making these changes then follow the steps given below.

Click on the Start button and open the Run box. In the Run box type NPCA.CPL and press enter. You might be prompted for Administrators password so please provide the same or just elevate the privileges accordingly. Click on the Networking Tab and then click on the configure button. In Configure window click on the Advanced tab and then on the Property box. Again just like we did above click on the Value drop down and select the value that represents the 100 Mbps Full Duplex setting and click on OK in the two windows for letting the changes take affect. Some network cards do not work properly if manual change is made in the Duplex settings. So for such network cards or if you face any issue after making the above mentioned changes, change the settings back to Automatic.