Windows backup
Regular windows backup:My Documents
C:\Documents and Settings\User Name\My Documents\
I think the most important folder on your computer is My Documents because it holding your personal documents. It is intended to be a user's common repository for documents and folders. This folder usually already includes the My Music folder for music files and digital audio, the My Pictures folder for image files, and the My Videos folder for video files. Those folders usually take up a lot of space, and they are therefore recommended to be taken care separately. Check the Backing up My Documents topic for possible backup strategies for My Documents folder, and other related information.
* Start Menu
C:\Documents and Settings\User Name\Start Menu\
C:\Documents and Settings\All Users\Start Menu\
The file system folders containing Start menu items. These folders already include the user's program groups, user's Startup program group, common program groups that appear on the Start menu for all users, and the program shortcuts that appear in the Startup folder for all users. Recommended for backup if you don't want to lose your Start menu along with the program groups and icons.
* Desktop Items
C:\Documents and Settings\User Name\Desktop\
C:\Documents and Settings\All Users\Desktop\
The file system directories used to store file objects and shortcuts on your desktop and on the desktop for all users. Recommended for backup if you want to keep your desktop icons and shortcuts safe and secure.
* Favorites
C:\Documents and Settings\User Name\Favorites\
C:\Documents and Settings\All Users\Favorites\
The file system folders that serve as a common repository for the user's favorite items. These favorites are usually displayed in the Internet Explorer menu. For some users this might be quite a large collection of links they have been collecting for years, the collection they may be wanting to keep safe and saved.
* Recent Documents
C:\Documents and Settings\User Name\Recent\
The system shell directory that contains shortcuts to the user's most recently used documents. They are listed in the My Recent Documents submenu of the Start menu. In most cases backing up is not that necessary.
* SendTo Locations
C:\Documents and Settings\User Name\SendTo\
The system shell folder that contains Send To menu items. These items may be backed up.
* Internet Cookies
C:\Documents and Settings\User Name\Cookies\
The file system directory that serves as a common repository for Internet cookies. Cookies are a means of saving web-site information, such as browser settings, user preferences, personal information, and passwords, on the client machine. If you surf on the Internet a lot, it is recommended to back up cookies.
* Internet History
C:\Documents and Settings\User Name\Local Settings\History\
The system folder that serves as a common repository for Internet history items, such as typed URL's etc. Internet Explorer's AutoComplete feature uses this collection, so you may want to back it up.
* C:\Windows\
C:\Windows\System32
The Windows system folders contain a lot of system application components, such as .exe, .dll, .ocx and more. The note from above applies to Windows system locations as well. Although you can choose to back up Windows folders, this backup won't help you much if you ever want to re-install Windows.