Outlook stores it's data in .pst files, located in C:\Documents and Settings\username \Local Settings\Application Data\Microsoft\Outlook.
Everything from local settings onwards are hidden folders so you will have to enable the show hidden files and folders option (Tools-folder options-view tab from Windows Explorer) to see past this point.
You may have problems directly accessing the .pst file from another PC if you install the drive as slave, and boot from a master using a different profile. Windows applies security priveleges to the .pst file based on the user profile that created the file. (i.e. protection for your emails on shared PCs).
If you replace the mboard, you should still be able to boot from the original drive (ok a few drivers may complain and you may get a 640x480 screen), but you should be able to open Outlook, then export your data to a backup.pst file that can be opened (or restored) on any PC.