Back to the Windows Error page Common Windows Error Messages

Error 645: Internal Authentication Error

Runtime error 645 can be caused by a number of things. It can be a conflict with either a generic Dial-Up Networking (DUN) error or a corrupted installation of DUN. This may leave the computer or modem in an irresolvable state; therefore, future connection attempts are not going to work as expected. To correct this error, you must first attempt to re-boot your computer. If that fails, we will guide you through additional steps.

How to Re-Boot Your Computer and Modem
  1. Save all unsaved work and close all programs.
  2. Click on the Windows Start button and select Shut Down.
  3. Check the circle next to Restart and click on the Yes button.
  4. If you have an external modem, turn its power off then on. If there is no on/off switch on the modem, you may have to unplug the modem's power supply.
  5. Once the computer has finished booting up, retry your NetZero connection.
  6. If you still receive this error message, please follow the instructions below to configure Windows network components for DUN and modify your system settings.
Configuring the Windows Network Components for Dial-Up-Networking

The following instructions are for those systems that are not on a Local Area Network (LAN). If you are on a LAN and follow these directions, you may create a conflict that will disrupt your computer's connection to your LAN. Please contact your network administrator for assistance before you continue making any changes to the system configuration.
  1. Click on the Windows Start button.
  2. Point to Settings and select Control Panel.
  1. Double-click the Network icon.
  1. What you will find listed under the Configuration tab will depend on your version of Windows. NetZero requires three network components total, but you may have more or less listed. The three that are required are:
    • Client for Microsoft Networks
    • Dial-Up Adapter
    • TCP/IP
    Note: You may see TCP/IP->Dial-up Adapter grouped together.

If Client for Microsoft Networks is not listed, you will need to add it:

  1. Click on the Add button.
  1. Double-click on Client.
  1. From the Manufacturers list, select Microsoft.
  1. From the Network Clients list, double-click on Client for Microsoft Networks to add it to the list.

    Note: This may automatically add all three components.

If Dial-Up Adapter is not listed, you will need to add it:
  1. Click on the Add button.
  1. Double-click on Adapter.
  1. From the Manufacturers list, select Microsoft.
  1. From the Network Adapters list, double-click on Dial-up Adapter to add it to the list.
  2. Click OK to exit.

    Note: You may see TCP/IP->Dial-up Adapter grouped together.

If TCP/IP is not listed, you will need to add it:
  1. Click on the Add button.
  1. Double-click on Protocol.
  1. From the Manufacturers list, select Microsoft.
  1. From the Network Protocols list, double-click TCP/IP to add it to the list.
Once you have confirmed that the three required Network components are installed, ensure that TCP/IP is correctly configured.



Check Network Settings

  1. On your desktop, double-click the My Computer icon.
  1. Double-click the Control Panel icon.
  1. Double-click the Network icon.
    Note: In the Primary Network Logon drop-down menu, ensure that Client for Microsoft Networks is selected.

  1. Double-click TCP/IP->Dial-Up Adapter.

    Note: If you get a TCP/IP Properties Information window, click OK.
  1. Ensure that only the circle next to Obtain an IP address automatically is checked.
  2. Select the WINS Configuration tab.
  1. Ensure that only the circle next to Disable WINS Resolution is checked.
  2. Select the Gateway tab.
  1. Ensure that all the fields are blank.
  2. Select the DNS Configuration tab.
  1. Ensure that the circle next to Disable DNS is checked.
  2. Select the Bindings tab.
  1. Ensure that only Client for Microsoft Networks is checked.
  2. Select the Advanced tab.
  1. Ensure that None is in the Property field.
  2. Select the NetBIOS tab.
  1. No changes are necessary.
  2. Click OK.
  3. Click OK to exit.


Next, you will need to set up this computer's identity.

  1. Select the Identification tab at the top of the Network properties window. We will want to change the entry here for Computer Name.

    Here is an example:
    • Computer Name:  NetZero
    • Workgroup:  Workgroup
    • Computer Description:  Mine
  1. Click OK.
You may now be prompted for the Windows CD-rom, or the file copy may begin automatically. If prompted for the Windows CD, insert the CD and click OK. If you are still prompted for it after clicking OK, verify that the drive letter listed in Copy files from is your CD-rom drive.

Note: If, during this process, you see a warning about "Version Conflict" or "A file being copied is older," click No. If you are prompted that the "file is not found," you are not using the CD-rom that was used to install Windows on your machine.

If you made any changes or added any components, you will be prompted to restart. Click Yes. When Windows restarts, you may see a dialog box asking for a Username and Password to log in. For Username, enter the same name that you entered for Computer Name in the prior step in the same lower case format. Do not enter a Password. Click OK. If asked to confirm, click OK.



Removing the Windows Password List

Windows 95/98 maintains a list of password files where any active passwords are stored, including the password for NetZero. Sometimes they can be corrupted or become non-functional. To resolve this problem, you will need to replace the password file.

To remove the Windows .pwl files

  1. Click on the Windows Start button, point to Find and click Files or Folders.
  1. In the Named field type *.pwl
  2. In the Look in field, select (c:) or the location where Windows is installed.
  3. Click Find Now.
  4. When Windows has found the .pwl files, click Select All from the Edit menu, then press Delete (or DEL) on your keyboard. These are generally harmless files, but it is recommended that you DO NOT empty your Recycle Bin until the software is fully functioning.
  5. With all .pwl files removed, perform a complete shutdown of your system and turn the power off. Wait about 10 seconds and restart the computer.
  6. Depending on your system, you may be prompted for a username and password at start up. If this happens, enter a username in all lower case characters (8 maximum) in the Username field and leave the Password field blank. Once you click OK, you will be prompted to confirm the password. Leave this field blank and click OK again. You should no longer see that prompt.

    Note: If you add a password at this time, you will be prompted to type a password every time you start your computer.

  7. Retry your NetZero connection.


Uninstalling / Reinstalling Windows Dial-Up Networking (DUN)

These directions are for those systems that are not on a Local Area Network (LAN). If you are on a LAN and follow these directions, you will create a conflict that disrupts your computer's connection to your LAN. Please ask your network administrator for assistance before making any changes to your system.

To start, close any active connections, as well as any other programs that you may have open on your system.
  1. Click on the Windows Start button.
  2. Point to Settings and select Control Panel.
  1. Double-click on the Network icon.


There will be a number of network components in the configuration tab. Any of these protocols or adapters could be causing connection problems. To eliminate the possibility of file corruption or misconfigured settings, we recommend that you remove and reinstall all three of the components listed below: To uninstall the network components please complete the following instructions:
  1. Highlight the first component in the list and select Remove.
    Note: If you are on a LAN (Local Area Network), do not remove the network adaptors and protocols. Please contact your administrator for instructions. If you use AOL, do not remove AOL Adaptor or TCP/IP.
  2. Continue until all three of the components listed above are removed.
  3. Click OK.
  4. If prompted to Restart the System, click NO.

    At this point you should be back in Control Panel.
  1. Double-click Add/Remove Programs icon.
  2. Select the Windows Setup tab.
  1. Double-click on Communications.
  1. Uncheck Dial-Up Networking.
  2. If you are prompted with a message that Dial-Up Networking is required by other components, click Yes.
  3. Click OK.
  1. When back at the Windows Setup tab, click Apply.
  2. Double-click on Communications again.
  1. Recheck Dial-Up Networking.
  2. Click OK.
  3. When back in the Windows Setup tab, click OK again to save the settings.
You may now be prompted for the Windows CD-Rom, or the file copy may begin automatically. If prompted for the Windows CD, insert the CD and click OK. If you are still prompted for it after clicking OK, verify that the drive letter listed in Copy files from is your CD-rom drive.

Note: If, during this process, you see a warning about "Version Conflict" or "A file being copied is older," click No. If you are prompted that the "file is not found," you are not using the CD-rom that was used to install Windows on your machine.
During the File Copy, you may see a window asking you to enter a computer name and workgroup name. Click OK. You will see the Network Identification window: At this point you should be back at the Control Panel again. Double-click the Network icon again. Some of the components that you previously removed will now have returned.




Identifying and Disabling 56k Modems

This procedure will disable any 56k protocols that your modem supports. While this will slow down the modem's initial connection rate, it will stabilize the connection.

Note: NetZero does not support 56K X2.

From region to region, the quality of the phone lines will vary. In some areas, your phone lines may not support high speed modem connections due to phone lines of marginal quality. Please contact your local phone company for details in your area. In order to get a stable connection, you will need to identify your modem and place an extra setting (or INIT STRING) in Modem properties.


To identify your modem

  1. Disconnect any active connections and reboot the computer if necessary.
  2. Click on the Windows Start button.
  3. Point to Settings and select Control Panel.
  1. Double-click on Modems.
  2. Select the Diagnostics tab.
  1. Select the Com Port that the modem is on and click on the More Info button.
You can find the name of the manufacturer listed under the Command and Response table of the More Information screen. You may see US Robotics, 3Com or LT WinModem. If you own a Rockwell modem, the listing for ATI3 would be either a number in the form 2.x.xxx.x or 2.xxx_k56flex. A 56k Cirrus Logic modem would be indicated by CL-MD-56xx or something similar.

To add the Extra Setting:
  1. Click on the Windows Start button.
  2. Point to Settings and select Control Panel.
  1. Double-click the Modems icon.
  1. Highlight your modem and select Properties (NOT dialing properties).
  1. Select the Connection tab.
  2. Click on the Advanced button.
  1. At the bottom, there is a field called Extra Settings.
  1. Click OK, then click OK again.
  2. Click on the Windows Start button and select Shutdown.
  3. Restart your computer.
When your computer is back up, retry the NetZero connection.

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