Go to Microsoft's Description of the Windows Installer CleanUp Utility page.Here
Scroll down and click the link Download the Windows Installer Cleanup Utility package now.
Save the file on your Desktop.
Double-click on the downloaded file to install the Windows Installer Clean Up utility.
To remove traces of your installation from your computer:
Go to Start > Programs > Windows Install Clean Up to launch the Windows Installer Clean Up.
In the dialog that appears, select the installation you want to uninstall.
Launch Windows Explorer by pressing Windows key + E or select Start > Explore.
Go to the location where the installation has installed the files, usually C:\Program Files\NameofCompanyorApplication, and manually delete them. To do this, select all the files (Ctrl +A or Edit > Select All) and hit the Delete key.
When installing an application for the first time
Error 1605 occurs when the installation thinks that the application has already been installed once on your computer. This causes the installation to run in Maintenance mode; however, it fails in the process because a previous instance of this installation does not exist on your computer. One of the reasons why this happens is because a property called REINSTALLMODE has been set incorrectly within the installation. Follow these steps to run the installation with the correct REINSTALLMODE property.
Select Start > Run.
In the Open field, type
Windows NT 4.0, 2000. or XP: cmd.exe and click OK.
Windows 95 / 98 or ME: command.com and click OK.
At the MS-DOS prompt, type in the path, or location, of setup.exe along with the REINSTALLMODE property, e.g., <PATH>\setup.exe /V"REINSTALLMODE="omus"
Press Enter. This runs the installation again with the correctly set property.
Install the ISScript engine
Another known solution to this issue is to install the ISScript engine on your computer. To install the ISScript engine, refer to Update to the Latest InstallShield Installation Engines.