running a windows file server online
 

on a windows 2k server machine, what software enabled to run an online file server with administrative UI and so on?

:)

the authorized users must be able to upload and download data. no ftp, all http.

iis, microsoft ftp. or wu ftp

or you could run apache for windows if you dont like iis

No ftp. IIS will run, but I need a backend solution that will enable users to upload data as well.

you have to enable web-directories and login for remote users,
but this will increase serious your security !!!
get better *nix

I can help you secure whatever solution you want to go with; *nix or Windows. Unix/linux would be tighter and more stable, IMO.