Saving Emails In Netscape

I just need to know how to save all of my emails to a zip disk in case something happens to my pc. I’ve tried the back-up/restore functions, but goofed up somewhere. I seem to have back-up some of the folders, but can’t get the systems restore function to work. It won’t let me access my “D” drive where I backed up some folders. Just tell me how I can save all of my emails and I use Netscape. Thx, mh