Windows Installer 3.1 v2 (3.1.4000.2435) is available
To update the 32-bit and 64-bit versions of Windows Server 2003 SP1, or to update the 64-bit versions of Windows XP, download the hotfix that is described in Microsoft Knowledge Base article 898715 instead of the 893803 (v2) package. The version number is 3.1.4000.2435.
Uninstall or remove apps and programs in Windows - Microsoft Support
There are different ways to remove apps and programs, so if you can't find the one you're looking for, you can try another location. Note that some apps and programs are built into Windows and can't be uninstalled. You can try to repair a program first, if it's just not running correctly.
Fix problems that block programs from being installed or removed
The Program Install and Uninstall troubleshooter helps you automatically repair issues when you're blocked from installing or removing programs. It also fixes corrupted registry keys. First, you'll need to download the troubleshooter. Download troubleshooter. If you see the File Download box when you start downloading, select Run or Open.
Install Quick Assist
For the best experience, download and install the new version of the Quick Assist app from Microsoft Store. If you have problems installing Quick Assist, here are some steps to try to get it installed and working properly. Select Start > All apps > Microsoft Store. In the Microsoft Store, search for and select Quick Assist. Select Get.
How to troubleshoot Windows Installer errors - Microsoft Support
When you install, uninstall, or update a program on a Windows-based computer, you may receive one of the following error messages. The Windows Installer Service could not be accessed. Windows Installer Service couldn't be started. Could not start the Windows Installer service on Local Computer. Error 5: Access is denied.
Use the Office offline installer
Download the offline installer from your account portal. To download the offline installer, go to www.office.com . If you're not already signed in with the Microsoft account associated with your copy of Microsoft 365 or Microsoft 365 do that now.
Uninstall or remove apps and programs in Windows
There are different ways to remove apps and programs, so if you can't find the one you're looking for, you can try another location. Note that some apps and programs are built into Windows and can't be uninstalled. You can try to repair a program first, if it's just not running correctly.
Update drivers manually in Windows - Microsoft Support
Learn how to update drivers in Windows using Device Manager to update or reinstall a driver.
How to check if an app or program is installed in Windows 10
To find out if an app or program is installed in Windows 10, select Start > Settings > Apps.
"Windows Installer Service could not be accessed" error message when ...
Run Instmsiw.exe for installer 2.0 again; this corrects the broken security key for the MSI service.