Need a little more info. Like What kind of themes? I'm assuming these are Window Blinds themes. If that's the case look in your task bar for an icon that looks like a painters pallette. Right click on it and select configure WindowBlinds. Scroll to the left. The first 2 chioces are Windows Classic and Windows XP style. Select either one and apply. Close the configure window. If this works, right click the icon for WindowBlinds one more time and this time select Unload WindowBlinds. This will unload WindowBlinds from the Computer's memory and it won't reload automatically when you reboot. That's about as much as I can help you. There are others who will be around probably tomorrow. Good Luck! And, don't worry what they've done won't hurt your computer. They probably found the free trail version of WindowBlinds and some fun.