Is there anyway to lock the command prompt? I need my computer to require a password to use the command prompt.

I lock the workstation occasionally but sometimes I forget and if I could just prevent my roommate from doing the "c: net user user *" to change my password it would be great.

I do not want to have to use the rundll.32 user command with script to automatically lock the computer. Just a way to lock the c prompt.

Sorry for not saying this earlier, I'm running a vista 32bit Asus gene II motherboard with a core i7 CPU

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    If you disable cmd.exe, that won't stop him from just pasting the same command line into the Run dialog. And neither of those stops him from opening your case and removing the hard drive. Lock your computer up or get a new roommate. =) – mindless.panda Jun 4 '10 at 17:21
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    Plus, I have to tell you that "physical access" == "they own your computer". Even if the machine is physically off, it's trivial to boot up from a CD or USB device and gain access to data on the hard drive. – Michael Todd Jun 4 '10 at 18:32
  • If they're willing to pull open your PC to access your data, you have serious issues... – Dentrasi Jun 4 '10 at 18:40

For your purposes, no, not really. There are so many work-arounds that by the time you've closed them all, your system is entirely unusable for anyone. If you block cmd.exe, He can still use the run dialog. He can still download an executable onto your system and run it which will do the same thing.

What you probably want to do is set your screensaver to launch after 5 minutes, and require a password to wake/go to welcome screen (depending on how your computer is configured). This will auto-lock your system after being idle for 5 minutes. Also get in the habit of just pressing Win+L (lock the system) when you leave keyboards but leave your account logged in. That goes for anywhere that you have your own user account (school computer labs, work computers, etc.). Just make it habit so that the screensaver is a fallback on the rare occasion you forget.

Further, I would disable booting from CD-ROMs and USB sticks / external harddrives in your BIOS, and set a BIOS password. This will prevent him from using a live CD to change your password without physically opening up the system to reset the CMOS - at which point, you do indeed have serious issues with your roommate. If it gets that bad and your computer has a spot for a lock, buy one.

He's probably just trying to play pranks / mess with you, unless you have reason to believe otherwise.

  • unfortunately my asus has a cmos restart button on the outside of the case – allindal Jun 4 '10 at 20:16
  • @allindal Ah, lovely. Thanks, ASUS! Hopefully it won't come to that ;) Or if it does, maybe he won't figure that part out. I would still disable CD-ROM booting, however. ophcrack.sourceforge.net is one of many tools that are otherwise at his disposal. – Darth Android Jun 4 '10 at 20:20

If you want people to not mess around, lock your computer. It's the simplest and most effective solution.

If you're worried they they'd boot into a liveCD, or pull out your disk, you can use full disk encryption (truecrypt), but you've got bigger problems.

You can't protect a computer if it's logged in as you, without crippling it beyond normal use. Just get in the habit of locking your machine - perhaps set the screensaver time to quite short, and have it require a password for screensaver.


Um, locking down a computer is a huge ordeal and no simple task. I assume you are running Windows XP so here's instructions on how to do it on XP.



Windows key + L


Set the screen saver time to be really short (a minute is the shortest time you can get from the UI) and tick the "On resume, password protect" option.

The really short time will annoy you when using the machine, but will pretty much guarantee that your room-mate would have to jump on the machine as soon as you left it - which you would notice!


on the bios/cmos reset issue you could do whole disk encryption with truecrypt to prevent access to the data on the drive.


I would think you could simply rename the 'net' command. I really have no idea if anything in the OS depends on it, and if there would be side-effects, though.

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    Renaming system files rarely ends well. – Dentrasi Jun 4 '10 at 18:37

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