I want to access and play media files on machine S (Windows XP) from machine C (Windows XP). Using Windows File Sharing ("share this folder" stuff), if it works, I would share the folder containing media files on machine S, and I would be able to play media files, sitting in front of C, using any media player I want. Windows somehow ensures that the remote files behave like local files.

But Windows file sharing won't work for me, is there any alternative?

If two machines were both Linux, I would install an SSH server on S and use Nautilus from C to access and play media files.

The reason why I can't use Windows file sharing is, my campus use two different subnets, I have S and C on different subnets and it seems that the firewall governing the whole network in campus doesn't allow file sharing between different subnets. I tried changing Windows Firewall settings on S to allow C in, it still wouldn't work, so it must be the other firewall.