Why is there no prompt to elevate user rights?

Question

Windows

Good day! There is a computer with windows 7 SP1, there are two users on it: Administrator and User (the level of rights corresponds to the names). The computer is not in an AD domain. Usually, when you try to perform an operation that requires administrator privileges, a UAC window appears prompting you to enter the password of an account with such rights. On this machine, this does not happen, for example, I start the installation of the application, the installer reports that administrator rights are required and completes the installation. I choose from the context menu "Run as administrator" - the same story. I even try to run the command line as administrator - it runs as a normal user. Clambered local security policies - everything is "standard". I do not understand why this is happening, I hope for your experience and help.