what port or ports are used for File sharing in windows?

I've seen all of these..file sharing related

UDP-137, UDP-138, TCP-139,TCP-445

And possibly TCP port 135, though that may be something to do with something called "RPC". [1]

on an windows 7 machine all of those are listening. Some are related to NETBIOS so you can do start...\\compname

This site http://ntsecurity.nu/papers/port445/

If the server has NBT enabled, it listens on UDP ports 137, 138, and on TCP ports 139, 445. If it has NBT disabled, it listens on TCP port 445 only.

And this site http://www.petri.co.il/whats_port_445_in_w2k_xp_2003.htm mentions

"In Windows 2000/XP/2003, Microsoft added the possibility to run SMB directly over TCP/IP, without the extra layer of NetBT. For this they use TCP port 445. "

So in 2K,XP,2003...and I suppose Win 7,8, it is possible to run file sharing on only port 445 But you'd be doing start...\\ip rather than start..\\compname

[1] http://www.danielmiessler.com/writing/windowsfilesharing/