The solution I used to solve this is basically one developed by
"nortel", but I put all the steps together in one place to make it
easier for others. Here's the procedure:
Instructions (for WinXP) to fix:
Error 720: A connection to the remote computer could not
be established. You might need to change the network settings
for this connection.
Note that a key sympton of this problem is that the modem
connects and then disconnects just after trying to register
the computer on the remote network.
These instructions were compiled from a couple of sources:Publish Post
Note that you can't uninstall TCP/IP in XP, which is why I
wrote up this version, but the procedure is basically the same.
Step 1: Uninstall the WAN Miniport (IP) and WAN Miniport (pptp)
MPORTANT: 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
about how to back up, restore, and edit the registry, click the following
number to view the article in the Microsoft Knowledge Base: 256986
(http://support.microsoft.com/kb/256986/EN-US/) Description of the Microsoft
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
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.
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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.
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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:
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)
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.
This worked for me and has worked for others.
Note that if you don't want to uninstall the two WAN Miniport devices,
you can disable them in the Hardware Manager and then proceed with
the reinstall as described above. This has the advantage of being more