When installing any program that uses the Windows Installer, I get the following error message: "Error 1500 - Another installation is in progress. You must complete that installation before continuing this one."
I've done a spyware cleanup, and disabled unnecessary startup programs in MSCONFIG. I've tried running the Microsoft Installer Cleanup Utility, but it returns the same error message. I tried in safe mode, but the Windows Installer does not run in safe mode. Because of another posting I saw on this problem, I looked for the follwing registry key to delete, but it wasn't there - HKEY_Local_Machine\Software\Microsoft\Windows\Installer\InProgress.
Any help will be greatly appreciated.