To backup your emails you'll need to find them - if you use outlook express I think they are .dbx files. so search for all the .dbx.
It may be somewhere like c:/ doc&set/user/local set/ app data/id/db (with lots character/microsoft/outlook exp
If you use anothr email find out what extension it uses & search for it
Lastly, don't reinstall m/soft - go & install one of the linux versions or get a mac - you won't look back