win32us.exe is a process belonging to an adult content dialer application that automatically tries to disconnect you internet connection and then dial a toll number. This process is a security risk and should be removed from your system.
If found on your system make sure that you have downloaded the latest update for your antivirus application.
Non-system processes like win32us.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you
check your registry to identify slowdown issues.