I want to install wincc but it says it is installed on your computer, I checked all the programs, it is not installed, I deleted the SQL Server program, it is still the same and we cannot solve this problem.

Hello,

        Without some screenshots or more information from you, it is not possible to offer exact suggestions. I can tell you that once you have started uninstalling, tinkering, and trying to reinstall software that the windows OS may be beyond fixing at this point. Over the years, I found it is far easier to remove the licenses and format Windows to a known good state. WinCC depends on many components like .Net Framework, IIS, Message Queuing, etc to be a in prefect condition prior to installation. There are many compatibility limitations as well with other programs (can't have existing full SQL for example prior to wincc install),  so it is far quicker to start with a fresh Windows OS (compatible release with your flavor of "wincc") and then install WinCC. Do not change the computer name nor Windows user after the installation as this only cause you more work. Once it appears working, image the pc so that you always have a known good state of which to return if there is a future problem. Saves a lot of time.

Thanks,

Steve