This happen to my PC over at work. The network seems fine. It’s kinda weird to me as the DHCP does not assign any IP to my PC but i can browse files over network. Tested, it really allowed me to copy, move, execute data over network.
I tried to see my IP configuration thru ipconfig. Nil, zero and no IP. Again, frustratingly tried to ping my gateway. It came out with an error message. This is the keyword that brought me to solution. “IP Driver Error Code 2″

First page Google result brought me to Microsoft’s KBase. “How to remove and reinstall TCP/IP on a Windows Server 2003 domain controller“. This is the summary and happened to led me to tears of joy.

I skip the first 4 steps as is irrelevant to me. I’m using XP by the way. The remaining resolution worked like a charm.

5. Click Start, and then click Run.
6. In the Open box, type regedit, and then click OK.
7. Locate the following registry subkeys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Winsock
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Winsock2
8. Right-click each key, and then click Delete.
9. Click Yes to confirm the deletion of each key.
10. Close Regedit.
11. Locate the Nettcpip.inf file in %winroot%\inf, and then open the file in Notepad.
12. Locate the [MS_TCPIP.PrimaryInstall] section.
13. Edit the Characteristics = 0xa0 entry and replace 0xa0 with 0×80.
14. Save the file, and then exit Notepad.
15. In Control Panel, double-click Network Connections, right-click Local Area Connection, and then select Properties.
16. On the General tab, click Install, select Protocol, and then click Add.
17. In the Select Network Protocols window, click Have Disk.
18. In the Copy manufacturer’s files from: text box, type c:\windows\inf, and then click OK.
19. Select Internet Protocol (TCP/IP), and then click OK.

Note This step will return you to the Local Area Connection Properties screen, but now the Uninstall button is available.
20. Select Internet Protocol (TCP/IP), click Uninstall, and then click Yes.
21. Restart your computer, and then select Directory Services Restore Mode as mentioned in steps 2 - 4.
22. In Control Panel, double-click Network Connections, right-click Local Area Connection, and then select Properties.
23. On the General tab, click Install, select Protocol, and then click Add.
24. In the Select Network Protocols window, click Have Disk.
25. In the Copy Manufacturer’s files from text box, type c:\windows\inf, and then click OK.
26. Select Internet Protocol (TCP/IP), and then click OK.
27. Restart your computer.

There you go.