Problem with the LAN Connection

I have selected “Obtain IP address automatically” in TCP/IP properties of Network Connection. After some time Internet doesn’t work & while checking the Local Area Connection’s support tab, there is 0.0.0.0 in IP Address, Subnet Mask and Default Gateway which resolves after restarting the PC.
Surprisingly text with the repair button shows “Windows did not detect problems with this connection. If you cannot connect, click Repair.”
What possibly could be the reason and how to eradicate this problem?
