cool computer prank by bhanu agrawal

(1)Visit your friend's house. Make sure they have a computer running Windows XP or Vista, and that you have access to their user account.
(2)Secure their current user settings. Purely optional, this will ensure you still have a friend when you're done. Create a new user account and copy over their existing user settings. When you're done with the prank, they'll be able to restore the changes you've made by referencing the other account. This is more important for the "black screen" prank than the "static background" prank.
(3)Wait until your friend goes out of the room. Anytime they leave the room for at least a couple of minutes will suffice.
(4)Once they are out of the room, close everything that is open on the computer.
(5)Right-click on the desktop background and select "Arrange Icons By", then select "Show Desktop Items" to uncheck it. It may take a moment for the effects to be made. If your friend's computer doesn't show the "Show Desktop Items" option, you may move all of their desktop icons (user created ones, not the Recycle Bin, etc.) to a different folder. You may also hide desktop icons such as "My Documents", "My Computer", "Internet Explorer", etc. by right-clicking on the desktop, selecting "Properties", clicking on the "Desktop" tab, and then clicking on the "Customize Desktop..." button.