netclient.exe is a process belonging to the Net Administrator remote administration tool which if installed without your knowledge can allow attackers to access your computer, stealing passwords, Internet banking and personal data and control your computer. This process is a security risk and should be removed from your system.
Non-system processes like netclient.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues