I neglected to discuss what to back up in my March 16 post. So here goes:

1. The folder "My Documents". Everything in here gets copied to another source. In this folder is the "My Pictures" and the "My Music" folder. If you use all the Windows defaults, all your pictures and iTunes music should be in this folder. If you use programs that put your picture and/or music in folders other than "My Documents", you are going to need to figure out in what folder(s) that information lives.

2. The folders "Favorites" and "Desktop". To find these folders, open up your "C" drive. Click on Documents and Settings/(Your user name). Copy the Favorites and Desktop folders to an external source.

3. Email. This is where is gets tricky. If you use internet-based webmail, you are in luck. No backup is necessary. If you use Outlook or Outlook Express, backup becomes a bit harder.
Outlook: All of Outlook's information is contained in a PST file. To find it, open the C drive, click on Documents and Settings/(User name)/Local Settings/Application Data/Microsoft/Outlook. Copy this whole folder to an external source.
Outlook Express: To find the databases that make up Outlook Express, open the C drive. Click on Documents and Settings/(User name)/Local Settings/Application Data/Identities.  In this folder are weirdly names folders with lots of letters and numbers. Copy these folders to an external source. See this link on more info about backing up Outlook Express email and contacts.

4. Programs cannot be backed up in Windows unless you do a full image copy. To do this, you need a program like Norton Ghost or Acronis True-Image.
MAC Backup:If you are using OS X 10.5 (Leopard) or above, you can use Apple's nifty Time Machine program. Just plug in an external drive, go to the System Preferences panel and initiate Time Machine. The program will automatically back up your documents, pictures, emails, programs.

If you have an older version of OS X (10.4 or lower), you'll have to manually copy the documents, music, pictures, video folders in your Home folder to an external source. See this link for how to back up your email and contacts.