If a breakdown on your old computer means you need to leave it behind, you don't need to abandon your email in the process; they can be recovered. Your emails, contacts and settings can all easily be backed up and used with your new setup, and you don't need a degree in computer science to do it. All you need to do is find your data, back it up and place it in the right spot on your new computer.
Find your data. For computers running Windows XP, your Windows Mail emails and settings are stored in "C:\Documents and Settings[user]\Application Data\Windows Mail," replacing "[user]" with your Windows user name. Vista and Windows 7 users should look in " C:\Users[user]\AppData\Local\Microsoft\Windows Mail."
Back up your "Windows Mail" folder. Drag the entire folder to an external hard drive. This could take a long time, depending on how many emails you have saved.
Retrieve the files from your backup onto your new computer or your fresh installation. Drag the entire "Windows Mail" folder to "C:\Documents and Settings[user]\Application Data\Windows Mail" if you use XP or "C:\Users[user]\AppData\Local\Microsoft\Windows Mail" if you use Vista or Windows 7. Start Windows Mail and your settings should be restored completely.