Error message when you try to activate Windows 7 or Windows Vista: "An error has occurred"

Method A: Use Microsoft Knowledge Base article 950756

This method is rated: Moderately easy.

For more information about how to resolve this error message, click the following article number to view the article in the Microsoft Knowledge Base:

950756 Error message when you try to activate a copy of Windows by using the Windows Activation wizard: "The Software Licensing Service reported that the product key is invalid: 0xC004F050

If this method worked, you are finished.

If this method did not work for you, you might want to ask someone for help, or you might want to contact Support for your next steps. Note Assisted support is no longer available for Windows Vista.

Method B: Verify your product key and use the "Change product key" feature to reactivate Windows

This method is rated: Easy.

If you were directed to this method, you entered an incorrect product key. See the product packaging to make sure that you have the correct product key. Then, follow these steps to use the "Change product key" feature and reactivate Windows:

1. Click Start , click Computer, and then click System properties on the toolbar.

2. In the Windows activation section, click the Change product key. If you are prompted for an administrator password or for confirmation, type your password, or click Continue.

3. In the Product key box, type the product key, and then click Next.
   
   Note Check the product packaging to make sure that you are entering the correct product key.

4. Follow the steps in the Windows Activation Wizard to complete the activation process.

If this method worked, you are finished.

If this method did not work for you, go to method G.

Method C: Use the "Change product key" feature to enter your product key again

This method is rated: Easy.

If you were directed to this method, you have the correct product key, but you have to try entering it again to reactivate Windows. To do this, follow these steps:

1. Click Start , click Computer, and then click System properties on the toolbar.

2. In the Windows activation section, click the Change product key. If you are prompted for an administrator password or for confirmation, type your password, or click Continue.

3. In the Product key box, type the product key, and then click Next.
   
   Note Use your original product key.

4. Follow the steps in the Windows Activation Wizard to complete the activation process.

If this method worked, you are finished.

If this method did not work for you, go to method G.

Method D: Verify that the product key is compatible with your version of Windows

This method is rated: Easy.

If you were directed to this method, your product key may not be compatible with your version of Windows. For example, if you have a 32-bit version of Windows, and you purchased a 64-bit upgrade of Windows, the new product key will not work with your current version of Windows. You can only upgrade a 32-bit version of Windows to another 32-bit version of Windows.

To complete this method, follow these steps:

1. Determine whether you have a 32-bit or 64-bit version of Windows. To do this, follow these steps:

   1. Click Start , type system in the Start Search box, and then click system in the Programs list.

   2. The operating system appears as follows:

      • For a 64-bit version operating system: 64-bit Operating System appears for the System type under System.

      • For a 32-bit version operating system: 32-bit Operating System appears for the System type under System.

2. See the product packaging to determine which version of Windows the product key is intended for (32-bit or 64-bit).

3. If the versions are different, you will have to obtain the correct version of your upgrade.

For more information about all compatible upgrade options for Windows Vista, click the following article numbers to view the articles in the Microsoft Knowledge Base:

932616 Installation choices for consumer versions of Windows Vista (32-bit only)

932795 Installation choices for 64-bit consumer versions of Windows Vista
  If this method worked, you are finished.

If this method did not work for you, you might want to ask someone for help, or you might want to contact Support for your next steps. Note Assisted support is no longer available for Windows Vista.

Method E: Obtain a compatible version of antivirus or DRM software

This method is rated: Moderately easy.

If you were directed to this method, your antivirus software or Digital Rights Management (DRM) software is incompatible with Windows.

To obtain a compatible version, follow these steps:

1. Contact the software manufacturer of the antivirus software or of the DRM software to obtain a version that is compatible with Windows.  For more information about this issue in Windows Vista, click the following article number to view the article in the Microsoft Knowledge Base:

   931699 Error message when you use Windows Vista: "An unauthorized change was made to your license"

2. Follow the steps in method B to reactivate Windows.

If this method worked, you are finished.

If this method did not work for you, you might want to ask someone for help, or you might want to contact Support for your next steps. Note Assisted support is no longer available for Windows Vista.

Method F: Verify that your Internet connection is working

This method is rated: Moderately easy.

To complete this method, follow these steps:

1. Click Start, and then click Help and Support.

2. In the Search Help box or in the Search online Help box, type Troubleshoot network and Internet connection problems, and then click Search Help.

3. In the list of topics, click Troubleshoot network and Internet connection problems.

4. Click the link that best describes the problem that you are experiencing.

5. Follow the suggestions to troubleshoot the problem that you are experiencing.

6. When you are finished, follow the steps in method B to reactivate Windows.

If this method worked, you are finished.

If this method did not work for you, go to method G.

Method G: Activate Windows by using the automated telephone system

This method is rated: Easy.

To complete this method, follow these steps:

1. Click Start , and then click Computer.

2. Click System properties on the toolbar, and then click Click here to activate Windows now in the Windows activation section.
   
   If you are prompted for an administrator password or for confirmation, type your password, or click Continue.

3. Click Show me other ways to Activate.

4. Click Use the automated phone system, and then follow the instructions that are provided.

If this method worked, you are finished.

If this method did not work for you, you might want to ask someone for help, or you might want to contact Support for your next steps. Note Assisted support is no longer available for Windows Vista.