Experiencing loss of default gateway after a restart. After restart, ipconfig shows 2 lines in default gateway. First line is 0.0.0.0, second is 192.168.1.1 (which is the correct value). However there is no connectivity. System details as follows: MB is ASUS P5GC-MX/1333, Core 2 Duo E7200 processor, Atheros L2 Fast Ethernet 10/100Base-T Controller (onboard). OS is Windows 7 Home Premium 64Bit. Uninstalling the driver for the NIC and then scanning for hardware changes and allowing system to automatically reload drivers fixes the problem until the next reboot.
More about :atheros fast ethernet 100base controller loses default gateway
Did you try using a static IP address or setting the LAN speed to 100 Mbps Half-Duplex or 100 Mbps Full-Duplex instead of Auto? If that doesn't work, you could install a PCI NIC that has official Windows 7 support.