169.254.x.x
IPCONFIG /RELEASE (type in cmd and press enter, incase of vista - type cmd in start search and in the search result - right click - run as administrator)
IPCONFIG /RENEW
Check Service Pack - "winver"   SP1 SP2
  Delete winsock from registry - HKLM - SYSTEM - CurrentControlSet - Services - Winsock & winsock2 NETSH WINSOCK RESET CATALOG
  IPCONFIG /FLUSHDNS
  Restart the Computer - Check the IP_ADDRESS Restart the Computer - Check the IP_ADDRESS
       
Power cycle modem
Check the IP_ADDRESS
Try system restore(optional)
Start - run - C:\Windows\INF - NetTCPIP - Right-click the file and select Install.
PC Restore or OSRI
Refer to ISP - Hard modem reset or Replace Modem