Net.exe is a process belonging to the Microsoft Windows Operating System and offers additional functions to your local area network via the DOS command line. This program is a non-essential process, but should not be terminated unless suspected to be causing problems. This process can sometimes be used by trojans but is otherwise a legitimate process.
Note: net.exe is also a process which is registered as the w32.dabber.c worm. This virus is distributed via the Internet through e-mail and comes in the form of an e-mail message, in the hopes that you open its hostile attachment. The worm has its own SMTP engine which means it gathers E-mails from your local computer and re-distributes itself. In worst cases this worm can allow attackers to access your computer, stealing passwords and personal data. This process is a security risk and should be removed from your system.