1. Computing
in FDAC :: Computer Locker What happens with your machine when you need to move away from the computer for 10 or more minutes? How secure is your data? Can someone sit on your chair while you are at a coworkers office and play with your data? Maybe you need a computer locking tool that is small and easy to use yet powerful enough to make sure your machine is locked when you need to go out for a break.

This is the 47th entry to the Fancy Delphi Application Contest

Read the full article to find more about (+ download source code) Computer Locker

When you download the application and test, rate it:

  1. Excellent
  2. Superb
  3. Good
  4. Average
  5. Poor
If you already voted, take a look at poll results.


December 9, 2008 at 9:21 am
(1) rpoulin says:

I’m locked out of my computer since i have compiled and run the computer locked out application. At first start of the application my password was wrong and the system shutdown. Since then i’m licked out! PLEASE HELP!.

December 9, 2008 at 11:09 am
(2) Claude says:

Hmm… I’m looking at the source code and not seeing anything obvious. I’m guessing (hoping) that Zarko ran this before he put it out here so maybe he would have a better idea.

December 9, 2008 at 6:24 pm
(3) Mahdi says:

I am locked out my computer me too please help me the password is wrong

December 9, 2008 at 7:07 pm
(4) ThievingSix says:

To stop the application from automatically starting after reboot you need to start the computer in safe mode. From there you can either remove the registry value from the RunOnce key, or you can replace the executable with a clean one.

I personally haven’t had any problems with this application but there are bound to be bugs with anything. For starters the password isn’t your Windows password. Second the password is stored on the executable in an MD5 hash then there is an MD5 for the MD5 of the password just in case anything went wrong.

Are you sure you typed the password right? Was caps lock on when you created the password or was entering it in? Any information would be helpful as to why it failed.

December 9, 2008 at 7:15 pm
(5) Mahdi says:

Thanks to Allah i am on now, who his computer locked, he can access to directory of application by MS-DOS and delete the file “computerlock.exe”
to delete the file by MS-DOS type the following command
del comput~1.exe

December 9, 2008 at 7:21 pm
(6) Yves says:

How can I?

As soon as I start (Windows XP), it opens up Computer Lock…

December 9, 2008 at 8:34 pm
(7) Silver Warior says:

It seems that this application has some bug wich prevents program to ask for a password but it only starts with I don’t know wich password. You can prevent program from starting the nex time you reboot, by boting into Windows safemode and then use regedit to remove it from “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce”
Also another bug changes some registry settings wich change your start menu to hide “Turn of compuiter” option. Only thing that it stays is “Log off”. And first time I runed this program it also hided my QuickLaunch toolbar.

December 9, 2008 at 8:42 pm
(8) ThievingSix says:

Alright, the problem was that the people that are running the precompiled version are running the one that Zarko compiled with his own password. Make sure to compile it yourself!

Zarko, I recommend uploading a newer version =(

December 9, 2008 at 8:57 pm
(9) Willson says:

The password please!!! I got the executable to try it!:(
I went in safe mode and changed the application name, but the first time I reboot I got “C:\documents” not found error and now I dont have nothing in my RunOnce also hide “Turn of computer” I need help!!! lol
I have Delphi7 and I couldnt compile it.
I needed just ten minutes without nothing to do lol
Oh Boy what a mess!!!
help help help

December 9, 2008 at 8:59 pm
(10) SilverWarior says:

I also don’t like that the program is changing some settings of my start bar, like NoChangeStartMenu, NoClose, NoLogOff) because if it comes to some problem with the program, those settings remain as they were so it can happen that because of this you lose ability to use windows your start menu is changed (no Turn off Computer, etc.). Also disabling Task manager on a way that this program does can even lead to event where user loses ability to use TaskManager. For fixing this you need to alter windows registry. And for those Who might having this kind of efekts I’m including contents of a windows registry file wich wil correct it.

You need to create a text file, then copy the text wich is between * below into it, and save it. After that you need to rename it into
Restore.reg and double click it. It will ask you if you want to import information from this file into registry. You need to confirm this. After importing settings to registry you need to log off from your windows acount and log on again for changes to take effect.

Windows Registry Editor Version 5.00




December 9, 2008 at 10:26 pm
(11) ThievingSix says:

The application is supposed to be a secure locking system. Once correctly logged in the application reverts to the original settings.

December 10, 2008 at 4:04 am
(12) Zarko Gajic says:


If you are running a precompiled version, the password is:


:( sorry for the mess. Who said programming isn’t fun :)

December 10, 2008 at 5:34 am
(13) SilverWarior says:

@ThievingSix When you are correclty loged in the aplication doesn’t revert to the original settings, but to the settings that are prespecified in aplication. But to do as you say the application would have to read original settings before it locks donw the system and then restore them after login. Also what happens if for some instance the application file gets damaged and aplication cannot be runed again on next reboot. The settings are then left incorectly. So it would be a good idea to store these settings in some file so that they can be fixed later in case of problems with the aplication itself. I would also like to see an option wich would alow you to chose if this aplication locks all users acces to the computer or only for a current user.

December 10, 2008 at 10:21 am
(14) ThievingSix says:

Hmm, the settings that get changed aren’t something I noticed. Didn’t realize that =). Also, that’s a good option to include.

Thanks Zarko ;)

December 10, 2008 at 11:38 am
(15) Claude says:

Wow, looks like you guys had fun :D

I was just wondering if people didn’t know about Windows+L key combination? I suppose if you are in a pre-xp environment it may not work… or if you don’t have a password on your log-in name.

Regardless, nothing faster than that when you need to jump up and get something while at work.

December 10, 2008 at 3:44 pm
(16) ThievingSix says:

Huh, never knew about the Win+L combo. Only reason I prefer this over the standard windows locking is that the computer can just be restarted to unlock it.

December 11, 2008 at 11:14 am
(17) Claude says:

Yeah, that’s true. Seems like an interesting program either way. Nice work to whoever wrote it.

December 11, 2008 at 5:33 pm
(18) ThievingSix says:

Thanks. I’m not sure if I want to block the Win+L though, since there is essentially a log off button there. But I do want to fix the registry settings that might get overwritten if you use them.

December 12, 2008 at 4:52 pm
(19) Hema says:

While locked, try this : ctrl+alt+del, start, run, cmd, tasklist to find PID, taskkill /f /pid PID. It is not so secure after all. (Win XP + SP3)

December 12, 2008 at 5:29 pm
(20) ThievingSix says:

That’s purely subjective. This was meant to run perfectly on my configuration which has Ctrl + Alt + Delete that shows the windows security panel not the start menu. The source code is provided to change it up if need be =)

December 13, 2008 at 9:17 am
(21) Hema says:

Message that taskmanager is disabled shows taskbar. I just want to show weakness,not to criticize.

March 23, 2009 at 6:52 pm
(22) Peace says:

This program is alright.

Its offensive secureity though.

Zarko! Please can we have a winner for the FDAC? I eagerly awat your reply

April 4, 2009 at 1:44 pm
(23) mohamed says:

Help neeeeded, please real all

am a student in IT institute

i am developing my graduation project
its a program named desktop locker

I am alone, no supervisior and no one to help me.

my problem is that i dont know, what OR how to do that
i will tell you what i have did, and plz plz plz.
give me your opinion and advise

when my program lock the computer it does:

1- lunch Topmost form with full screen,no borders
2- it listens to move and resize MSG’s and it prevent them
3- it makes a timer that will make my program on top every 1 milie second, and it checks if the active widown is from our process or not

4- it blocks all the (alt or ctrl or win) keys
5- it blocks the shutdown operation, un less it is forced
6- it blocks the minimze command even if it used by code like shell.minimizeall
7- it blocks the autorun on the CD ROM
8- it blocks the task manager form the registery
9- it listens to WM_SHOWWINDOW msg, and if it is hide, it will start a timer after 1mili sec to show my form, i did like that because i couldnt prevent the hiding operation
10- i make a dynamic class name for my form, this will change the class name for my form every time i lunch the program
11- hide the taskbar
12- disable and hide the desktop

i think that is all what i did to prevent any one to use the computer, unless he unlock it with a password

iam not sure if this is a good way or not.
give me opinions and advises
iam alone
help me
i need a profesional opinio and advice
and any one,any one who has an idea, plz tell it to me

August 12, 2009 at 3:08 pm
(24) friedrich says:

I’ve recently seen simiar freeware application written in Delphi that does the same as Yours. It’s called Marxio Timer. So far, I haven’t see better tool to lock my PC when I’m out.
I’m not a producer of this app, but I like it and think it should be on place #47 :)

December 28, 2009 at 7:20 pm
(25) TDI6speed says:

:( sorry for the mess. Who said programming isn’t fun :)

Please clean up the mess.
Your precompiled version is still downloadable,
on 28-dec-2009 from

I was locked out of my computer for hours.

March 10, 2010 at 7:48 am
(26) Putut says:

Password IS “opg”
thanks to Zarko Gajic

December 12, 2010 at 10:40 pm
(27) reibna says:

got the pass. mr zarko, where did you put “opg” on your source code? which one is the one for correct password. thanks.

June 26, 2012 at 4:17 am
(28) Zarko Gajic says:

@Reibna, the password is not hard-coded to “opg” in the source code – only in the executable version.

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