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"The Windows Installer Service Could Not Be Accessed" error when you try to install a program in Windows 7 or Windows Vista
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Applies to: Windows 7 EnterpriseWindows 7 Home BasicWindows 7 Home PremiumWindows 7 ProfessionalWindows 7 StarterWindows 7 UltimateWindows Vista BusinessWindows Vista EnterpriseWindows Vista Home BasicWindows Vista Home PremiumWindows Vista StarterWindows Vista UltimateMore
When you try to install a program in Windows 7 or Windows Vista, you receive the following error message:
"The Windows Installer Service could not be accessed. This can occur if the Windows Installer is not correctly installed. Contact your support personnel for assistance."
To resolve this issue, use Method 1. If Method 1 does not resolve the issue, use the next method that is listed until you resolve the issue.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: 322756 How to back up and restore the registry in Windows
To reset the Windows Installer Service settings in the registry, create a registry file by using Notepad. Then, run the file to update the registry key.
To do this, follow these steps:
Click Start, and then type Notepad in the Search box.
Under the Programs heading, click Notepad.exe.
Copy the following text, and then paste it into a notepad: