I have done this one several times… its always good:
- Go to your victims (I mean friends) computer and click the PRINT SCREEN button on the keyboard
- Paste that image into PAINT (or whatever you want to use) and save it as a .JPG
- Now set the WALLPAPER to be that .JPG
When the victim comes back to the machine, the screen will appear normal but over time as they move or delete icons, it will get very funny.
More April Fools Gags Gold
