It is not as much as a networking problem as filesharing misconfiguration. Previously, you had SAMBA installed (and probably pre-configured for your setup) on you linux box - SAMBA is the means to share files amongst windows and linux hosts. I don't know what you have changed since then but it is obvious that SAMBA isn't running ( and possibly not configured if installed) on your linux box. You can download samba from
http://samba.org/ and search here on how to configure it.
Good luck.