Recovering important data when Windows wont boot

A task that frequently appears in computer repair jobs is retrieving the data on the clients PC when a hard drive has failed (or failing) or Windows wont boot and they want me to do a Reinstall. This article is intended for people who are comfortable working in DOS or some other command line, however if you are a beginner a GUI tool such as Ultimate Boot CD will be extremely helpful.

Here is how to retrieve clients personalized data such as emails, favorites and their documents when Windows does not work.

Emails:
Emails can sometimes be a little tricky as Microsoft likes to hide the location of these.
Here are the default locations of the Microsoft email clients:

Outlook Express
Emails: C:\Documents and Settings\User Account\Local Settings\Application Data\Identities\{Random Numbers and Letters}\Microsoft\Outlook Express

Address Book: C:\Documents and Settings\User Account\Application Data\Microsoft\Address Book\User Account.wab

Microsoft Outlook
C:\Documents and Settings\User Account\Local Settings\Application Data\Microsoft\Outlook

Favorites:
C:\Documents and Settings\User Account\Favorites

My Documents:
C:\Documents and Settings\User Account\My Documents

Desktop:
C:\Documents and Settings\User Account\Desktop