>i wanted to make it restart the computer if the wrong passwords entered
That's one of the worst ideas I've ever heard. What if other users are logged onto the system? Are you going to kill their session just because somebody fat-fingered a password? What if this program is installed on a server?! If the whole idea is to make one person wait for the computer to reboot so that brute forcing the password would take a painfully long time, why don't you just lock the account for X minutes?
If this is the extent of your security design skills, I highly recommend you not try to make an ad hoc system. Instead build on an existing and proven design, because all you're likely to do is create a huge mess that isn't nearly as secure as you think.
>ok but the main thing is its not anyones but mine
>the computer would only be used by me
>and the program would be made just incase my brother or sister try to go on
The guy who wrote DOS didn't expect Microsoft to buy it and turn it into a huge product. Rationalizing poor designs and sloppy code with "but it's only for me" is where a lot of the field's biggest headaches come from.
You still haven't indicated what OS you are using, but doesn't it do that for you anyway? On each one of Windows, Mac, and Linux you can set yourself a secure password and disable all other user accounts but yours.
That way, only the person who knows the password (you) can log onto your laptop. (Which is the same thing you are stated as doing.)
If it is just for leaving it lying around for a moment, you can always trigger the screensaver, which again on each system mentioned can password-protect the computer.
If you want a quick script to trigger the screensaver on demand I can give you one. There are also programs online that will do it if you move the mouse into a corner of the display or something like that...