When trying to upgrade or reinstall the software, the installation program states that the software or a previous version of it is already installed and must uninstalled before proceeding. After attempting to uninstall the software, it remains visible in the Windows' Control Panel > Add/Remove/Uninstall Programs list and installation still will not proceed.
Use Microsoft's Fix It tool:
Remove the key that tells the installation program that the software is still installed from the registry.
Select Start > Run or press Windows key + R
Type "regedit" into the Run dialog, click OK.
In the resulting Registry Editor, expand the tree in the left pane to find the following key (icon will appear as a folder) HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
Export this key in case it needs to be restored. This is done by right clicking the icon for the "Uninstall" key then selecting Export.
Use the Find tool to search for the name or part of the name of the software.
When a key is found, confirm the key is for the correct application by checking the values for DisplayName, DisplayVersion, and InstallLocation. If the key seems to be for a different application, press F3 to find the next key.
After confirming the correct key is currently displayed in the right hand pane, right click the icon that looks like an open folder in the left pane, then select Delete.
Press F3 (Find Next) to make sure no other relevant keys remain in the parent "Uninstall" key.
For 32-bit applications installed on 64-bit Windows, the following key may need to be substituted into step 3 of the above process.HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall
Note: Microsoft says "Serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry... view the article in the Microsoft Knowledge Base: http://support.microsoft.com/kb/322756"
Keywords: "Error: 1605 This action is only valid for products that are currently installed"P/S: 68478, 500000086442