Do not delete any of these profiles. You obviously have Hidden Files and Folders enabled, that's why you are seeing every profile on your computer. But if you have deleted a user account recently with one of these names then you can delete the profile as well. Every user account has an associated profile which contains the My Documents folder, Favorites, Desktop, Cookies, Local Settings, Start Menu, etc.
If I look at C:\Documents and Settings, I see seven folders:
Administrator, 24 MB
All Users, 751 MB
Default User, 23 MB
Local Service, 8 MB
Network Service, 0.3 MB
Ow, .8 MB
Owner, 8.6 GB
All Users, Default User, Local Service, Network Service, and Ow were last accessed 4 months ago.
All Users seems to be a subset of Owner.
Questions: Can I get rid of any of these? Are the files that are common to All Users and Owner taking up double the space?
Computer is Gateway, 3.2 GHZ, 2 GB RAM, 160 GB main drive.