If you’re trying to install something, such as iTunes or any other program and you are experiencing the dreaded error of: The Windows installer service could not be accessed, you have come to the right place for the right solution.
I have searched high and low for the solution. I finally figured it out.
You have to go into your registry.
Start, run, type in “regedit”.
Next go to HKEY_LOCAL_MACHINE.
To the right you’ll see WOW64. Double click on it, or right click on it and click on modify. Change the setting from 1 to 0.
Next, go to the start menu again and type in the search box: “services.msc”.
Look for and find the Windows Installer service.
Double click on it and tell it to stop. Next, tell it to start.
You should now be able to install your programs.