Click Start, type "regedit" and hit enter.

Navigate to HKEY_CLASSES_ROOT\Directory\Background\Shell.

Right-click Shell and choose New > Key and call it "Aero On" (without the quotes).

Right-click the Aero On key you've created, and create a new key called "command". In the right hand side of the console, double click on "Default" and give it the value Rundll32 dwmApi #102.

Right-click on the Shell key again, select New > Key, and call this "Aero Off" (again without the quotes).. Create a command key below it, as you've just done, and give it the value Rundll32 dwmApi #104.

Now, right-click on any empty part of your desktop, and select Aero On when you want to turn on the awesome effects like Flip 3D, and choose Aero Off when you're after the most amount of speed possible - for example when you want to play games.