Since you indicated Office, I'm going to assume that you are using Outlook 2000.
In WinXP... they will be under the user profile:
c:\Documents and Settings\userlogin\Local Settings\Application Data\Microsoft\Outlook\
In Win98... they will be in c:\program files\Microsoft Office\Outlook\
Both of the above are if you have accepted the default locations in Outlook 2000. If you are using Outlook Express, they may be in different locations or not.
When you copy the files to cd -- their attribute will be thereafter set to read-only. You will need to copy them back to hdd and right click on the files to remove (uncheck) the read-only attribute before you can use them on another computer.
If incoming e-mails are on the wrong computer, you need to look at e-mail settings (profiles) and software settings.