The NIC drops the connection occasionally.
Symptoms
1. You keep losing the LAN and the Internet connection. When that happens, the LAN icon in the tray shows "Acquiring network address". The ipconfig command receives 0.0.0.0 IP address.
2. The NIC drops the connection occasionally.
Possible solutions
1. Upgrade the NIC drive.
2. Re-configure the NIC speed and duplex.
3. Upgrade the router or switch firmware.
4. If it is wireless, it could be security settings issue. Try to re-create the wireless connection or change the SSID.