1. Unclick-able desktop

   Allright, this one is really old but sometimes users will not know what happened. Just make a screenshot of your desktop by pressing "Print Screen" on your keyboard (sometimes shown as "Print Scrn"). Now go to Paint and Paste (Ctrl+V). You should now have an image of your desktop. Save the image to your PC (not on your desktop) and save it as BMP. You'll now have the file like this: C:/Desktop.bmp.
   Next, right-click on your desktop and select Properties. Select the tab Desktop and click Browse... Navigate to your screenshot and press OK to set it as your background. You're almost done now.
   Right-click your desktop again and navigate to "Arrange icons by" and uncheck "Show desktop icons". There you have it, the icons on the desktop can not be clicked anymore.

2. Desktop upside down

   Do you still have the image from the previous prank? Open it again in Paint. Now rotate the image (Ctrl+R) and set it to 180 degrees. Save to file again as BMP, like this: C:/Potksed.bmp.
   Now set the image again as your background and there you have it: Your desktop is turned upside down. But wait: The taskbar at the bottom is still there? Right-click on it and select Properties. On the Taskbar tab, select the Auto-hide the taskbar check box. Press OK to save the changes.

pop-up trick

Hi everyone!
Here is a fun, funny, and easy way to annoy your friends and family members by (harmlessly) messing with their computers. This one is a simple batch file that makes a message box pop up that says anything you want. The trick: no matter how many times you click OK, the message will never go away! Have fun!

Step 1: The Batch File

1: Open notepad (under Start > All Programs > Accesories > Notepad
Copy and paste these lines into Notepad:

@echo off
:top
msg * Insert your message here
goto top

Be sure to delete "insert your message here" and replace it with your own message!

Step 2: Saving the File

Go to File and click Save As.

First look at "Save as File Type" near the bottom. It should say "Text Documents". Change it to "All Files".

Type the name of your file into the "File Name" box, and be sure to end it with ".bat" instead of ".txt"

Save it to your "My Documents" folder.

Step 3: The Funny Part

Now, if you click on the batch file (which should look like a box with a gear inside it) in your Documents folder, the message should pop up. It will only go away if you restart the computer.

To make it begin automatically when you (or someone else) logs in, copy the file from the Documents folder.

Go to "My Computer", then go to:
Local Disk > Documents and Settings > (Username of Person you want to annoy) > Start Menu > Programs > Startup.

Paste the batch file  into the Startup folder.

Now it will run whenever they log in, and the person will never be able to find it! Mwahahaha!