Ever on your new Windows 7 computer, whether it be a notebook or a desktop, and all of a sudden your windows seem to fade or disapper? Want to know what's causing it, or how to stop it from happening? Here's a solution:

They have moved the "show desktop" quick icon. It now appears on the lower left side of the screen, by default. They have also added a "peek desktop" feature of aero.

If you hover your mouse over the shadow par that the arrow is pointing to it will "peek" at your desktop if that option is enabled (which is why your are here!). It will say "show desktop".

Right click there (on the "show desktop" area the arrow is pointing to) and you will see two options. If you click the "show desktop" option, it will do exactly that, show your desktop. If you click the "peek desktop" option, it will toggle the check mark next to that option. Leave it unchecked, and you should no longer find your windows "disappearing".

Alternatively, you can right click on the big round start button, select "properties", and uncheck the "use aero peek to preview desktop" option.