This theme for Windows 7, is Smooth as butter and crispy.:) (Smile)
Installation instructions are inside in RAR.(WinRAR is recommended for extraction)

Update 1 :
Fixed an annoying caption button bug
Added Cursors,Fonts,Sounds (Selected Only)
Add a new theme variant
Added 2 new Space Wallpapers
Due to some complaints and to make it safe & simple, I HAVE REMOVED ALL EXE INSTALLERS.Now RAR contains only folders,theme files,Registry Tweaks and Start button.FEEL FREE TO DOWNLOAD
I won't describe much about this theme because it's key features given below will help you to decide whether to download it or not.
(Anyhow, you'll realize that 7MB download is worth it after using Nod)
Very smooth buttons,boxes and windows borders
70% Windows 7+20% Windows 8 +10% Mac OS=Aero Smooth
Extras included (Cursor/Fonts/Sounds)
Improved Blue progress bar.
Start button included
Registry tweak to resize window borders/caption buttons/scroll bars for best effects.
4 theme variants (only Window colors/sounds/wallpaper) & Discover More while using

Download Aero Smooth - A smooth,crisp theme for Windows 7

You need to copy theme in C:\Windows\Resources\Themes

Sumber : devianART