Hi,

I want to password protect my PC so my roommates dont use it when I'm not around. Not that I dont trust them, I just hate it when anyone else uses my PC except me! The windows password on start-up can easily be bypassed by simply hitting the cancell button and allowing acces to the computer. Is there anyway to alter this so you either must put in the password, or the computer wont allow you to move on?? Also, anyone know a good web site with Windows information?

Thanks in advance for the assistance!

Max

Sounds like Windoze 95 or 98.  With NT or 2000 that is no longer an issue...  (the cancel button)

Go into your computers BIOS and setup a bios password.  Without the password, they can't bootup into Windoze.

worked great,

Thanks!

Can the Windows 2000 password be recovered if you lost it?

Does anyone know a way?

Its not easy you must crack the password with brute force (its like guess and check but you do it quickly with a computer program)

Thanks, I'll check for one.

Bypassing the bios password is as simple as taking the case off and shorting a pin to reset the bios to defaults.  I did this in high school to gain access to the computer lab without authorization, but never got caught.  If I was in high school and did something like that now I'd be a federal felon.

NT passwords are no different.  I can change the NT/Win2K admin password with nothing more than a floppy disk.  If they've got physical access to the machine then none of the countermeasures you've enabled will keep them out if they're determined.  With that being said, they probably don't know about the things I just talked about, so you'll probably be safe with a BIOS password.

In Win98 you can also just set a screensaver password and make sure you set off the screensaver when you leave.  Of course, then they can just shut down the computer, or in some cases hit ctrl-alt-delete to bring up the task manager and kill the screensaver.  Microsoft fixed this bug, but there are a lot of people that don't have it installed.

God Bless Texas

You can try brute forcing the password with an application like l0phtcrack, which requires the sam file and a decent amount of CPU and time, or you can just use the Winternals NT admin kit and change the password if actually recovering it is not an option.

I'm an Information Security professional, or as I like to put it, professional hacker.  Unfortunately, the market is soft and doesn't take to us one trick ponies too well.  So until then I'm doing freelance work on the side and working IT contract jobs.

God Bless Texas

Actually, there's also a method of cracking known as a dictionary attack.  You basically compile a list of dictionary words and use them by themselves or in combinations to try and guess the proper password.  Dictionary attacks take very little time to run and are generally quite successful.  In IT organizations I've found that when a password integrity policy isn't established or enforced that it's painfully easy to crack the majority of accounts.  We're talking 75% or more accounts broken with just using dictionary words.  This also the most effective attack when strong encryption algorithms are used.

A brute force attack is much harder and much more CPU intensive, but using a few machines in parallel we were able to brute force passwords for various apps and the NT system passwords as well.  We'd have disgruntled employees leaving password protected documents or changing admin level account passwords and quitting.  It was our job to get access to the data and get the systems back up and running, among other things.  Using a strong encryption algorithm makes these attacks more resource intensive, especially when the bit length increases.

And there's also attacks against the specific cryptographic algorithm or implementation.  The latter is generally the most effective since most programmers implement even strong and sound cryptographic solutions poorly.

God Bless Texas