Implementing a shutdown timer in Windows 7

Every now and then, I find the need to shutdown my PC automatically at a specified time for some reason or the other. In my most recent case, I needed to shut my Windows 7 PC down at 8am in the morning anticipating a scheduled power shutdown in my block. While there are many GUI-based applications out there that could do this for me, I chanced upon a simpler solution detailed below:

1. Open the command prompt by going to Start, Run and typing cmd, or by simply typing cmd in the start menu's search box.
2. In the command prompt, type shutdown /? to get details about the shutdown command.
3. We will be using the /t xxx switch which specifies that we want to execute the command xxx seconds in the future. In my case, I wanted to do so 12 hours in the future, which according to calc was 12 * 60 * 60 = 43200 seconds away.
4. Using this information, type shutdown /s /t 43200 at the prompt and press enter. The /s indicates that we want to shut down the computer. /r and /h, on the other hand, stand for restart and hibernate respectively.
5. Windows should pop up a balloon alert confirming that the PC will shutdown at, in my case around 8 am.
6. To abort a scheduled shutdown, type shutdown /a.

This might work for Vista as well. While XP does have a shutdown function, I do not remember it to have a built-in scheduling feature.

I hope that this helps!

(I've pasted the help message for the shutdown command below:)

C:\Users\Jubal>shutdown /?
Usage: shutdown [/i | /l | /s | /r | /g | /a | /p | /h | /e] [/f]
    [/m \\computer][/t xxx][/d [p|u:]xx:yy [/c "comment"]]

    No args    Display help. This is the same as typing /?.
    /?         Display help. This is the same as not typing any options.
    /i         Display the graphical user interface (GUI).
               This must be the first option.
    /l         Log off. This cannot be used with /m or /d options.
    /s         Shutdown the computer.
    /r         Shutdown and restart the computer.
    /g         Shutdown and restart the computer. After the system is
               rebooted, restart any registered applications.
    /a         Abort a system shutdown.
               This can only be used during the time-out period.
    /p         Turn off the local computer with no time-out or warning.
               Can be used with /d and /f options.
    /h         Hibernate the local computer.
               Can be used with the /f option.
    /e         Document the reason for an unexpected shutdown of a computer.
    /m \\computer Specify the target computer.
    /t xxx     Set the time-out period before shutdown to xxx seconds.
               The valid range is 0-315360000 (10 years), with a default of 30.
               If the timeout period is greater than 0, the /f parameter is
               implied.
    /c "comment" Comment on the reason for the restart or shutdown.
               Maximum of 512 characters allowed.
    /f         Force running applications to close without forewarning users.
               The /f parameter is implied when a value greater than 0 is
               specified for the /t parameter.
    /d [p|u:]xx:yy  Provide the reason for the restart or shutdown.
               p indicates that the restart or shutdown is planned.
               u indicates that the reason is user defined.
               If neither p nor u is specified the restart or shutdown is
               unplanned.
               xx is the major reason number (positive integer less than 256).
               yy is the minor reason number (positive integer less than 65536).

Reasons on this computer:
(E = Expected U = Unexpected P = planned, C = customer defined)
Type    Major   Minor   Title

 U      0       0       Other (Unplanned)
E       0       0       Other (Unplanned)
E P     0       0       Other (Planned)
 U      0       5       Other Failure: System Unresponsive
E       1       1       Hardware: Maintenance (Unplanned)
E P     1       1       Hardware: Maintenance (Planned)
E       1       2       Hardware: Installation (Unplanned)
E P     1       2       Hardware: Installation (Planned)
E       2       2       Operating System: Recovery (Planned)
E P     2       2       Operating System: Recovery (Planned)
  P     2       3       Operating System: Upgrade (Planned)
E       2       4       Operating System: Reconfiguration (Unplanned)
E P     2       4       Operating System: Reconfiguration (Planned)
  P     2       16      Operating System: Service pack (Planned)
        2       17      Operating System: Hot fix (Unplanned)
  P     2       17      Operating System: Hot fix (Planned)
        2       18      Operating System: Security fix (Unplanned)
  P     2       18      Operating System: Security fix (Planned)
E       4       1       Application: Maintenance (Unplanned)
E P     4       1       Application: Maintenance (Planned)
E P     4       2       Application: Installation (Planned)
E       4       5       Application: Unresponsive
E       4       6       Application: Unstable
 U      5       15      System Failure: Stop error
 U      5       19      Security issue
E       5       19      Security issue
E P     5       19      Security issue
E       5       20      Loss of network connectivity (Unplanned)
 U      6       11      Power Failure: Cord Unplugged
 U      6       12      Power Failure: Environment
  P     7       0       Legacy API shutdown