You can`t detach as such but you can save them to your C drive in a specific file e.g.My Documents.
In Outlook Express highlight the e-mail with the attachments in the top right hand pane - it should then appear in the viewing pane beneath it. There will be a paper clip in the title bar of this pane. Left click this and then select SAVE ATTACHMENTS.
Click on the BROWSE button and then navigate to the My Documents folder by clicking on the + signs to highlight the right folder.