Hi,
There are four setting that are required for transparent icon
backgrounds:
1) Go to System Properties - Advanced tab - Performance 'Settings -
Visual Effects tab:
"use drop shadows for icon labels..." must be checked
2) Right-click on Desktop - Arrange Icons by - "Lock Web items..." must
be unchecked.
3) If there is any web content on your desktop, transparency won't work.
To check for web content: Display Properties - Desktop tab - Customize
Desktop button - Web tab - make sure all checkboxes are unchecked.
4) Wallpaper must be an image file, not html.