Hi you should try this -
Reset TCP/IP Settings.
If using a Laptop, make sure the wireless switch or button is turned on.
Replace the RAS PPPoE driver:
Open a Command Prompt as Administrator.
Select all the code below, then right click it and click Copy:
TAKEOWN /F "C:\Windows\system32\drivers\raspppoe.sys"
ICACLS "C:\Windows\system32\drivers\raspppoe.sys" /grant administrators:F
Right click in the Command Prompt window and click Paste.
Press Enter.
Once it has finished, close the Command Prompt.
Go to the following folder:
C:\Windows\system32\drivers
Rename the raspppoe.sys file to raspppoe2.sys
Right click on the following file and click Save Target As / Save link as:
Vista RAS PPPoE Driver.
Save it in the C:\Windows\system32\drivers folder.
Restart the computer.
If using a Modem, obtain the latest driver.
Reset your router.
Re-install your network card drivers.
If the problem still exist then you should other methods which you can found in this article -
Methods to fix error 651