When you try to install a program which uses Windows Installer in a Windows Vista computer, you may receive the following error.
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.

This error may occur even though Windows is already in normal mode.
Resolution
Start the Windows Installer service
- Click Start, type Services.msc and press {ENTER}
- Double-click Windows Installer
- Set the Startup type of Windows Installer to Manual
- Click Start to start the service. Note down the error message if any.
- Click OK.
Windows Installer Registry Fix
If the above steps do not help or if the Windows Installer service is not listed in the Services applet, follow these steps:
- Download msiserver.zip and save it to Desktop.
- Unzip the file and extract msiserver.reg to the Desktop.
- Right-click msiserver.reg and choose Merge.
- Click Yes when asked for confirmation.
- Restart Windows.
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- Determine the Target Path of Windows Installer Shortcuts
- Windows Vista Service Pack 2 Available for Public Download
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I am unable to extract the file specified from the downloaded file.
The downloaded file is being saved without any file extension although the Save As dialog box does specify the file type as ZIP file. Windows seems to think it’s a Microsift Word documnet (based on the icon used for the file). I do not have MS Word available on this machine.
When I Right Click on the downloaded file there is now menu choice of Extract or anything similar.
Can you provide any ideas on how I can extract and merge the msiserver.reg data?
I’m running Internet Explorer version 8 on Windows Vista SP2.
Thanks
Added this after updating the registry, and problem was resolved:
As Adminiatrator, run this from the command line:
regsvr32 c:\windows\system32\msi