(i'm on a rooted aria with android 3?)
it does work for me. i have a samba server on the phone that lets me access the sd-card from the 7 box, and ES file manager has a LAN tab that lets me access the Windows 7 box from the phone - actually a bit unsecurely as i can even browse the root of C: - which i find odd as it's not shared within the OS.
-forget about the "home group" or whatever that abomination is on 7. use the standard tried-out network functions.
-forget about the libraries as well - that seems like a semi-useless shortcuts collection/indexing scanario.
-do create passwords for the accounts that you want to use. i've ran into issues already in the XP era where empty passwords block network (et. al.) functions as programs expect to deal with a user/pass combo. if you're concerned about too much security, use admin/admin; share/share etc, whatever is easy to remember.
-there's issues on Windows 7 network authentication beyond the above, and while it may not be your issue, it may also well be. android is another graphical UI flavor of linux, so samba is at the core of network browsing: win7 group policy samba - Google Search