If you want to disable Shadow in Windows 8, refer to the tutorial below.
Shadow in the outside a windows is a special feature of Aero. Microsoft brought Aero in Windows Vista. Since then, it is the most popular theme in a windows operating system. Though Microsoft introduces Metro UI in Windows 8, still Aero is a edge ahead of Metro. Some people likes these shadow feature of Aero, some doesn’t. If you belong to the second group, here is a way to disable Shadow. Just follow the instructions carefully.
1. Switch to Desktop Mode by pressing Windows + M simultaneously.
2. To make out each change clearly, set solid white as desktop background.
First right-click on the desktop and click on personalize.
Next, click on Desktop background.
Now select solid colour white as desktop background.
3. Now press Windows + F and the Search window will appear. Type “Advanced System” without quotes and click on Settings.Then select View Advanced System Settings on the right.
4.Now click on the Advanced tab and then Settings.
5. Now the performance settings window will appear. Uncheck Shadow to disable.
Now, shadow has been disabled. You can check this from the screenshot below.