If you have uninstalled the siNetFilter Driver you can reinstall it.
1. Open your Network Properties Dialog (Start -> Control Panel -> Network Connections) right click on the network connection used.
Select "Properties" from the context menu to get the network configuration dialog.
2. Click the "Install" button to open the following dialog.
3. Select "Service" and click the "Add" button.
4. Select the siNetFilter Driver and click the “OK” button.
5. The setup will now try to install the siNetFilter Driver.
Press the "Proceed with Installation" button to install the driver for all NICs.
It may appear several times depending on the number of NICs in your system.
6. Close all dialogs with the "OK" button to apply the changes.