On the Windows XP machines, make sure "Simple File Sharing" is turned off.
Explorer -> Tools -> Options -> View -> (scroll to bottom of the list) Unckeck Simple File Sharing
Thanks, but I did this as well! Honestly, everything looks like its set up correctly on both OS's, but it just doesn't work...
Everyone is on the same workgroup and everything. The test shared folders I've created are shared with "everyone" and gives full control to the same in the security tab. But I'd imagine the problem isn't with the folders at all, since I believe the computer should still show up even if the folders aren't accessible to the user.
All computers are running 7/XP Professional, by the way, if that's important.