I have Windows Vista on my computer and whenever I login, I always have that aero theme. It's usually see-through/clear, but now it's not. How I can fix this?
To change Aero settings, right click on your desktop and choose "Customise"
You should then be able to choose "Window Color and Appearance" to change transparency and other options.
You can also click the text at the bottom "Open classic appearance properties for more color options." which should allow you to turn Aero off/on (Sorry, it is not very clear from your question what you are trying to do, so trying to show both solutions!)