Patches 1.4, 1.41, and 1.5 cannot be installed.

I've encountered this issue a couple of times. But through trial and error, I found a solution back then, and I'm recommending it now. You don't need to delete anything; just disable it. It might be recognizing the patch as a program invader and preventing it from performing its functions without prompting. However, it's also possible that there are incorrect registry entries. If the path is wrong, the patch might simply write files to a different directory. You can check the patch for bugs in the following way: install patch 1.5 (for example), and then try to install 1.1 (again, just an example). If the patch works correctly, it should prevent the installation of an older version.