Vista - can't play media in vista

I'm running Vista Ultimate on a pc. Xbox with xbox media center on the hard
drive so I can stream media from my pc, not Xbox360, Windows XP Home on a
pc.

I can't connect to any pc from my xbox when browsing via the workgroup
option in the xbox interface. It says workgroup not found. No workgroup.
Both pcs are on workgroup as the workgroup. In upnp I can connect to the
vista and xp home pc but only via the media sharing option on vista/windows
media player 11. With xp on both computers then i can connect from my xbox
through workgroup. When Vista is installed instead of xp on the vista pc
then i can't connect at all or see anything.

vista pc sharing is on as are the hard drives being shared as well with full
permissions. no firewall of anykind on vista either. i disabled it. i go
into vista sharing and network and turned on the sharing, password needed or
not needed does not matter. i have right clicked on a hard drive in vista
and shared it this way. inside media player 11 i set up media sharing as
automatically allow all devices and i told it to share my whole hard drive.

what gets me is with xp on all pcs then i have no issue, but when vista is
on then there are problems even though i have enabled file sharingt
correctly in vista. it seems vista does not work unless all computers are
vista or something like that.

also for some reason, in xbox it plays music not in order, but
alphabetically. if it is getting the music from xp then it's in order. i
dont get that. i hate that.