Hi,
look
here for background information.
The easiest way is to open a Windows Command Prompt (important: right click the Icon for Command prompt and select "Run as administrator") and enter the following command:
netsh advfirewall set allprofiles logging droppedconnections enable
Connect your Windows 8 PC to your modem. Wait a few minutes while surfing in the Internet.
Dropped packets will be logged in the file C:\Windows\System32\LogFiles\Firewall\pfirewall.log. If you are not allowed, to open it, just copy it to the desktop or somewhere else and open the copied file.
Stop logging by entering the following command in a command prompt you started with administrative rights:
netsh advfirewall set allprofiles logging droppedconnections disable
Post the contents of your pfirewall.log here for inspection.
PT