On most computers running Windows Vista, a problem somewhat strange, in fact, once you turn the computer can not connect to the LAN.
Investigating the network settings you find that the default gateway is deleted, and despite the reset, the next time you restart the computer the problem reoccurs.

Solution:
Open a DOS prompt window through Start - Run - type cmd and press enter
Type the following command: netsh ip reset
Then press enter and reset the IP address and gateway of the network card.
Since then the computer does not lose more setting the default gateway