CustoPack is a free all-in-one customization tool for Windows XP (32-bit), Windows Vista (32 or 64-bit), and Windows 7 (32 or 64-bit).
Using CustoPack, you can customize your icons, logon screen, desktop background, visual style and more, in a jiffy using CustoPacks themes. It downloads these themes from the official CustoPack gallery.
You can also create your own CustoPack by adding new icons, modified DLL files, logon screen, fonts, desktop background and visual style.
Download: CustoPack