PsExec works on NT 3.51, NT 4.0, Win2K and Windows XP.

Utilities like Telnet and remote control programs like Symantec's PC Anywhere let you execute programs on remote systems, but they can be a pain to set up and require that you install client software on the remote systems that you wish to access. PsExec is a light-weight telnet-replacement that lets you execute processes on other systems, complete with full interactivity for console applications, without having to manually install client software. PsExec's most powerful uses include launching interactive command-prompts on remote systems and remote-enabling tools like IpConfig that otherwise do not have the ability to show information about remote systems.

Installation 
Just copy PsExec onto your executable path. Typing "psexec" displays its usage syntax.

Usage 
usage: psexec [\\computer][-u user [-p psswd]][-s|-e][-i][-c [-f|-v]][-d][-][-a n,n,...] cmd [arguments]
   computer Direct PsExec to run the application on the remote computer. If you omit the computer name PsExec runs the application on the local system. 
    -u Specifies optional user name for login to remote computer. 
    -p Specifies optional password for user name. If you omit this you will be prompted to enter a hidden password. 
    -s Run remote process in the System account . 
    -e Loads the specified account's profile. 
    -i Run the program so that it interacts with the desktop on the remote system. 
    -c Copy the specified program to the remote system for execution. If you omit this option then the application must be in the system's path on the remote system. 
    -f Copy the specified program to the remote system even if the file already exists on the remote system. 
    -v Copy the specified file only if it has a higher version number or is newer on than the one on the remote system. 
    -d Don't wait for application to terminate. Only use this option for non-interactive applications. 
    -priority Specifies -low, -belownormal, -abovenormal, -high or -realtime to run the process at a different priority. 
    -a Separate processors on which the application can run with commas where 1 is the lowest numbered CPU. For example, to run the application on CPU 2 and CPU 4, enter: "-a 2,4" 
    program Name of the program to execute. 
    arguments Arguments to pass (note that file paths must be absolute paths on the target system)  

 
You can enclose applications that have spaces in their name with quotation marks e.g. "psexec \\marklap "c:\long name\app.exe". Input is only passed to the remote system when you press the enter key, and typing Ctrl-C terminates the remote process. 

If you omit a username the remote process runs in the same account from which you execute PsExec, but because the remote process is impersonating it will not have access to network resources on the remote system. When you specify a username the remote process executes in the account specified, and will have access to any network resources the account has access to. Note that the password is transmitted in clear text to the remote system. 
 
Examples 
The following command launches an interactive command prompt on \\marklap: 

psexec \\marklap cmd

This command executes IpConfig on the remote system with the /all switch, and displays the resulting output locally: 

psexec \\marklap ipconfig /all

This command copies the program test.exe to the remote system and executes it interactively: 

psexec \\marklap -c test.exe

Specify the full path to a program that is already installed on a remote system if its not on the system's path:

psexec \\marklap c:\bin\test.exe

Run Regedit interactively in the System account to view the contents of the SAM and SECURITY keys::

psexec -i -d regedit.exe
 
PsTools 

PsExec is part of a growing kit of Sysinternals command-line tools that aid in the adminstration of local and remote Windows NT/2K systems named 
PsTools.