One of our computers keeps saying it cant authenticate the certificate, what should i do?

Certificate issue comes when the date and time settings of the computer is wrong...in this case if the date is incorrect it cannot authenticate with the server and you will get certificate error so please check the system date time...if you like please rate thanks

If You cannot enable 802.1x authentication on computers running Windows 2000 because support for 802.1x is not provided by default in Windows 2000. Therefore, the associated user interface (the Authentication tab) does not appear in the Network Connection Properties dialog box.

A supported feature that modifies the product's default behavior is now available from Microsoft, but it is only intended to modify the behavior that this article describes. Apply it only to systems that specifically require it. This feature may receive additional testing. Therefore, if the system is not severely affected by the lack of this feature, we recommend that you wait for the next Windows 2000 service pack that contains this feature.

The following files are available for download from the Microsoft Download Center:
Collapse this imageExpand this image English Language Version (http://download.microsoft.com/download/win2000platform/patch/q313664/nt5/en-us/q313664_w2k_sp4_x86_en.exe)

After you apply this update, follow these steps to enable 802.1x authentication:

1. Installing the hotfix installs the 802.1x service in the disabled state. To change the Wireless Configuration service startup to Automatic: Right-click My Computer, and then click Manage. Click Services and Applications, and then click Services. Set the Startup value for the service to Automatic, and then start the service.
2. Open Network Connections by clicking Start, pointing to Settings, clicking Control Panel, and then double-clicking Network Connections.
3. Right-click the wireless connection for which you want to enable or disable 802.1x authentication, and then click Properties.
4. On the Authentication tab, do one of the following:
   • To enable 802.1x authentication for this connection, click to select the Enable network access control using IEEE 802.1x check box. By default, this check box is selected.
   • To disable 802.1x authentication for this connection, click to clear the Enable network access control using IEEE 802.1x check box.
5. In the EAP type box, click the Extensible Authentication Protocol type that is to be used with this connection.
6. If you click Smart Card or other Certificate in the EAP type box, you can configure additional properties if you click Properties and then follow these steps in Smart Card or other Certificate properties:
   • To use the certificate that is located in the certificate store on your computer for authentication, click Use a certificate on this computer.
   • To verify that the server certificate that is presented to your computer is still valid, click to select the Validate server certificate check box, specify whether to connect only if the server is located in a particular domain, and then specify the trusted root certification authority.
   • To use a different user name when the user name in the certificate is different from the user name in the domain to which you are logging on, click to select the Use a different user name for the connection check box.
7. If you click Protected EAP (PEAP) in the EAP type box, your Windows user name and password are used for authentication.
8. To specify whether the computer should try authentication on the network if a user is not logged on, if the computer or user information is not available, or both, follow these steps:
   • To specify that the computer try authentication on the network if a user is not logged on, click to select the Authenticate as computer when computer information is available check box. By default, this check box is selected.
   • To specify that the computer try authentication on the network if user information or computer information is not available, click to select the Authenticate as guest when user or computer information is unavailable check box.

"Error 766: A certificate could not be found. Connections that use the L2TP protocol over IPSec require the installation of a machine certificate, also known as a computer certificate."

"Error 766: The L2TP connection attempt failed because the security layer could not authenticate the remote computer."

Cause: Connections that use the L2TP protocol over IPSec require the installation of a machine certificate, also known as a computer certificate. You will see this error message when such a certificate is not available.

Typically, this error is generated on a remote access server that has active L2TP ports configured, the remote access service started but there is no certificate in the computer certificate store. This generates an event log message that tells the administrator that L2TP ports will not be able to accept calls until a certificate is acquired and RRAS is restarted.
Resolutions: 1. If you use PPTP VPN, select Automatic in Type of VPN.
2. If you use L2TP, check the remote access server and make sure there is certificate in the computer certificate store.

windows.microsoft.com/...vista/What-are-the-system-recovery-options-in-Windows-Vista

Hi, please check if the date and time of your computer is correct, if not then correct it then close and reopen your internet explorer. let me know if that works.

Access the preferred network settings (if you are using the Windows wireless setup - right click on the wireless icon + view available wireless networks + preferred networks) for your machine and edit the listing for your wireless network, you'll need to uncheck the box that says something to the effect of "an authentication key is provided for me" and enter your security key in the boxes provided.

If it still fails - you may want to remove your network from the preferred listing and add it manually, making sure that the authentication is turned off as described and with your security key entered twice.

xp : go to start --> control panel ---> on the top leff click on "switch to classic view" then open network and internet connections right click on the wireless conn. then from the upper tabs go to "Authentication"  your setting should be as following :
Enable IEEE 802.1x ....... (cheked) EAP Type : Smart Card or certificate Authenticate as computer ...... (checked) Authenticate as gues ..............(unchecked)
then click on "properties"
choose "use a certificate on this computer" and check "use simple caertificate ......" and check "Validate server certtificate" click ok till u close all the boxes 
:D hope that would work :D

Be certain the the number is on a tag saying COA (certificate of authenticity)
and that your using the one for the product you are registering.
or that a O is a zero