Had to reset default gateway. this loss of connectivity has happened before. I updated my driver for NVIDIA nforce 10/1000/1000 Mbps ethernet and it worked for months and now it is happenning again. This is very frustrating. I need some help!!!

Same problem here. Almost every day I loose Internet connectivity. The IP-address is still valid but the Subnetmask changed from 255.255.255.0 to 255.0.0.0 and the Default Gateway entry is empty. After ipconfig /renew the settings are corrected and connectivity is re-established. The problem started after I upgraded my HP Pavilion a6733nl from Windows Vista Ultimate to Windows 7 Ultimate (32 bit). The NIC-driver is Realtek PCIe GBE family controller version 7.6.820.2009 This is the latest Win7 driver available from hp.com. According to the hp-helpdesk, hp does only support the preinstalled o/s :-(