If your computer is configured to receive its IP address (Internet Protocol) dynamically and not statically, you may run into problems after a reboot where your computer refuses to accept a new address as the old ones lease has not yet run out. A message will tell you that your computer already has an address, and that a connection is impossible. Here is a solution which will fix your problem.
First start the Windows command line interpreter by clicking “Start”, selecting “Run” and typing “cmd” in the dialogue box that appears followed by Enter.
At the command line, enter the following command: “ipconfig /release” and press enter on the keyboard. Next, enter “ipconfig /renew” and press Enter. Everything is done and you should now have an up to date IP address.