笔记本拨号问题解决办法

If you are experiencing this when trying to use Dialup Networking (ThinkPad Modem) or Verizon VZAccess Broadband, the following may be useful. Note, the solution involves modifying the registry on XP so it is not for the faint of heart.

Note that a key symptom of this problem is that the modem connects and then disconnects just after trying to register the computer on the remote network.

Step 1: Uninstall the WAN Miniport (IP) and WAN Miniport (PPTP)

IMPORTANT: This procedure contains information about modifying the registry.

Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base: 256986

(http://support.microsoft.com/kb/256986/EN-US/) Description of the Microsoft Windows Registry

SYMPTOMS

When you try to use a dial-up connection to connect to your Internet Service Provider (ISP), you may receive the following error message during the "Registering your computer on the network" portion of the connection agreement:

Error 720 - the connection attempt failed because your computer and the remote computer could not agree on PPP control protocol.

Additionally, when you view the devices in Device Manager, you may notice a yellow exclamation mark (!) over the icon for the WAN Miniport IP (#2) device.

CAUSE

This issue may occur if the TCP/IP protocol has become unbound from the dial-up adapter, or if a conflict is created when a second WAN Miniport IP device driver loads.

RESOLUTION

To resolve this issue, uninstall the WAN Miniport IP and PPTP devices.

To do so, follow these steps:

1. Right-click My Computer, and then click Properties.

2. Click the Hardware tab, and then click Device Manager.

3. On the View menu, click Show hidden devices.

4. Under Network adapters, you will see WAN Miniport IP devices. If a WAN Miniport IP device is listed, continue to the following step. If no WAN Miniport IP device is listed, go directly to step 16.

5. Click Start, click Run, type regedit in the Open box, and then click OK.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

6. Locate the following registry subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-

08002BE10318}

7. On the Registry menu, click Export Registry File, type backup-key in the File name box, and then click Save.

Note You can restore the changes that you make to this registry key. To do so, double-click the backup-key.reg file that you saved.

8. Click each of the registry subkeys under this key, and then view the Data column of the DriverDesc value to determine which of the subkeys corresponds to WAN Miniport (IP). For example, the 0005 subkey.

9. Right-click the subkey whose DriverDesc value data is WAN Miniport (IP) or WAN Minport (PPTP); (for example, right-click 0005), and then click Delete. Click Yes to confirm that you want to delete the key.

10. Quit Registry Editor.

11. Right-click My Computer, and then click Properties.

12. Click the Hardware tab, and then click Device Manager.

13. On the View menu, click Show hidden devices.

14. Under Network adapters, right-click WAN Miniport (IP) and then click Uninstall. Click OK to confirm that you want to remove this device.

15. Repeat for the WAN Miniport (PPTP).

Step 2: Reinstall the WAN Miniports

1. Find netrasa.inf in c:\windows\inf

2. Make a copy of the file and name it netrasa.inf.save

3. Open the orignal copy of netrasa.inf and place a semicolon in front of the line that starts "Excludefromselect=\" and and continue with all follwing lines and then end with

"MS_NdisWanNbfIn,MS_NdisWanNbfOut" under the [ControlFlags] section. (all lines between)

Step 3:

1. Start a Add new hardware session (from Control Panel) and choose that the hardware is already installed. Choose to "Add New Hardware" and then select "Network Adapters" followed by "Microsoft" and then both the PPTP and the IP Wan miniport one at a time.

(NO need to reboot between these steps)

2. After you finish both then reboot.

3. Select Start -> Run and type: netsh int ip reset c:\resetlog.txt

(For details, see http://support.microsoft.com/kb/299357)

4. Reboot and try your connection.

5. Delete the modified netrasa.inf and rename the original (which was saved as netrasa.inf.save) back to netrasa.inf