If you ever wanted to install an app on your system Windows, but instead of it installing, you were greeted by Error message “Windows Installer Service could not be accessed", you don't have to worry because there is a very simple solution to solve the problem. you just have to follow the steps below.

How do we fix the "Windows Installer Service could not be accessed" error?

Open one Command Prompt (taste cmd in Start Menu or Start Screen), then, depending on the architecture of the system used, type the following commands:

If your Windows is 32-bit

• msiexec /unregister (to unregister the service msiexec.exe from the system)
• then msiexec /regserver (to register the service msiexec.exe back to system)

If your Windows is 64-bit

• type the commands first %windir%\system32\msiexec.exe /unregister and %windir%\system32\msiexec.exe /regserver (to unregister, then re-register the service msiexec.exe in the directory C:\Windows\system32)

• then type the commands %windir%\syswow64\msiexec.exe /unregister and %windir%\syswow64\msiexec.exe /regserver (to unregister and then re-register the service msiecec.exe in the directory C:\Windows\syswow64)

Then close Command Prompt yes restart WinXP, and after restart you will be able to install the desired applications in the system without any problem. Success!

STEALTH SETTINGS – How to fix “Windows Installer Service could not be accessed” in Windows