Transform Your Windows XP in Windows Vista without any Customization pack

Visual style (or theme)
Boot screen
Login screen
Sounds
Mouse Cursors
Windows Icons
Windows Explorer
Progress dialog box
Shutdown/log off dialog box
About Windows box
System Properties dialog box
Windows Classic Startmenu Left-side Image and Start button Logo
and a few other things
http://www.askvg.com/transform-your-windows-xp-in-windows-vista-without-any-customization-pack