Don't you hate it when people mess with your computer without you knowing it? Here are two ways to prevent this. Create a desktop icon to lock your computer, and password protect after the screen saver is activated. Both of these only work if you already have your computer password protected on login.

If you already have a password, skip to the next part.

To create a password, go to the control panel , then to user accounts .   Click your account, and then the " change my password " button, enter the requested fields and click on " change password " and then close the window.

How to create a lock-down icon:

First, pick any icon on your desktop. Right click it and drag it to another place on the desktop.   In the menu that appears select " copy. "   Now we need to change the name and the target of the new shortcut. Right click this shortcut, and click " properties. "   Make sure you are in the shortcut tab .  

In the box labeled " target, " copy and paste this line:

%windir%\System32\rundll32.exe user32.dll,LockWorkStation

In the box labeled " Start in, " copy paste:

%windir%

To apply these changes click " apply. "   Next you can change the icon.   Just click the " change icon " button.   If you're not already there hit the browse button and go to:

C:\WINDOWS\system32\shell32.dll

You'll find a nice selection of icons there.

Select an icon from the ones that appear in the box and click " ok. "

Now move to the general tab .   The box on the top contains the name of your icon.   Change it to whatever you want.   I used "Fun Game" in the hope that if someone comes to the computer and it is not locked that they will click this icon, locking the computer.   (This actually worked once!)   After you are finished, click " apply ," and then " ok. "

To test your icon, double click it. You should be taken to something like a log on screen.  Just enter the password to get back into windows, just as you left it too. This is different from actually logging off. Whenever you know you will be away for a while, just click that icon, and your computer will be safe.

How to lock down on screen saver:

Right click on your desktop in any empty space. Click " properties " in the menu that opens. Go to the screensaver tab.  All you have to do now is click the box next to " On resume, password protect ." Click " apply, " and then " ok. "

Let your screen saver run, and see what happens after you move your mouse. This is good in case you leave suddenly and forget to click the icon we made earlier.  Unlike hibernation, this will allow other programs, such as Kazaa or iMesh, to run in the background.

I found this especially handy in my college dorm to protect my computer from my computer science major roommate who always wanted to check out what I had on my machine and change a bunch of settings to his preference. For you maybe it's co-workers, or kids at home, but either way, this is really nice!