How do I stop/start a scheduled task on a remote computer programmatically?

I want to write a script that will stop a scheduled task on a remote computer, do some stuff, and then start the schedule task back up.

How can I do it?

Here's what I found.

stop:

schtasks /end /s <machine name> /tn <task name>

start:

schtasks /run /s <machine name> /tn <task name>


C:\>schtasks /?

SCHTASKS /parameter [arguments]

Description:
    Enables an administrator to create, delete, query, change, run and
    end scheduled tasks on a local or remote system. Replaces AT.exe.

Parameter List:
    /Create         Creates a new scheduled task.

    /Delete         Deletes the scheduled task(s).

    /Query          Displays all scheduled tasks.

    /Change         Changes the properties of scheduled task.

    /Run            Runs the scheduled task immediately.

    /End            Stops the currently running scheduled task.

    /?              Displays this help message.

Examples:
    SCHTASKS
    SCHTASKS /?
    SCHTASKS /Run /?
    SCHTASKS /End /?
    SCHTASKS /Create /?
    SCHTASKS /Delete /?
    SCHTASKS /Query  /?
    SCHTASKS /Change /?

Note: "schtasks" (see the other, accepted response) has replaced "at". However, "at" may be of use if the situation calls for compatibility with older versions of Windows that don't have schtasks.

Command-line help for "at":

C:>at /?
The AT command schedules commands and programs to run on a computer at
a specified time and date. The Schedule service must be running to use
the AT command.

AT [\computername] [ [id] [/DELETE] | /DELETE [/YES]]
AT [\computername] time [/INTERACTIVE]
[ /EVERY:date[,...] | /NEXT:date[,...]] "command"
\computername     Specifies a remote computer. Commands are scheduled on the
local computer if this parameter is omitted.
id                 Is an identification number assigned to a scheduled
command.
/delete            Cancels a scheduled command. If id is omitted, all the
scheduled commands on the computer are canceled.
/yes               Used with cancel all jobs command when no further
confirmation is desired.
time               Specifies the time when command is to run.
/interactive       Allows the job to interact with the desktop of the user
who is logged on at the time the job runs.
/every:date[,...]  Runs the command on each specified day(s) of the week or
month. If date is omitted, the current day of the month
is assumed.
/next:date[,...]   Runs the specified command on the next occurrence of the
day (for example, next Thursday).  If date is omitted, the
current day of the month is assumed.
"command"          Is the Windows NT command, or batch program to be run.

schtasks /change /disable /tn "Name Of Task" /s REMOTEMACHINENAME /u mydomain\administrator /p adminpassword 

What about /disable, and /enable switch for a /change command?

schtasks.exe /change /s <machine name> /tn <task name> /disable
schtasks.exe /change /s <machine name> /tn <task name> /enable

Try this:

schtasks /change /ENABLE /tn "Auto Restart" /s mycomutername /u mycomputername\username/p mypassowrd