How to access time limit for an application in XP Pro or Home edition?

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

/Create         Creates a new scheduled task.

/RU          username          Specifies the user account (user
                               context) under which the task runs.
                               For the system account, valid values
                               are "", "NT AUTHORITY\SYSTEM" or
                               "SYSTEM".
/SC          schedule          Specifies the schedule frequency.
                               Valid schedule types: MINUTE, HOURLY,
                               DAILY, WEEKLY, MONTHLY, ONCE,
                               ONSTART, ONLOGON, ONIDLE.
/ST          starttime         Specifies the time to run the task.
                               The time format is HH:MM:SS (24 hour
                               time) for example, 14:30:00 for
                               2:30 PM.
/TN          taskname          Specifies a name which uniquely
                               identifies this scheduled task.
/TR          taskrun           Specifies the path and file name of
                               the program to be run by this
                               scheduled task.
                               Example: C:\windows\system32\calc.exe

cacls      Displays or modifies access control lists (ACLs) of files
/E            Edit ACL instead of replacing it.
/P           user:perm  Replace specified user's access rights.
                    Perm can be: N  None
                                        R  Read
                                        W  Write
                                        C  Change (write)
                                        F  Full control  


sirbounty;
 I hope you don't mind me elaborating why this would work, but catch a man a fish and he eats for a day, teach him HOW to fish and you feed him for life.

Thanks for both, I will split the points for both of you as close on time.

Thanks again

After rethink about the case, the answer above may not solve my problem. However it is my fault for not specifying the question clearly.

Because the above solution will need the computer to be on all the time and in my case, I would like to limit my son for playing his favorite game for too long everyday, would it be possible to achieve below:

After my son logs on to his computer, he can only play his game (one or two application) for 2 hours a day?

I have thought to use the login script but still can not figure it out. If you can answer this, I will allocate another 100 points for new answer.

Thanks again.

I know a few parents that use WatchDog and it seems to work great for them, and is relatively cheap.

http://watchdogpc.com/

There's other parental management software out there like Wallfly etc, but WatchDog is the only one I've personally seen.