Question : I can see other computer, but others cannot see my computer

Recently, I bought a Switch 8 port 10/100 to establish a small home network with only 2 computers, both using Windows XP Pro SP2, I connect both computers to the switch, and 1 port connect to my ADSL Router. Both computers can access internet.
I start the "Setup a home or small office network" wizard on both computers, and leave every settings on default, and turn on file and printer sharing on both.

Both can see each other on the same workgroup. The funny problem is, comp A can access shared folder on comp B, but comp B cannot see or access shared folder on comp A ?! I try everything, turn off all firewalls on comp A, but it's still there, when I double click comp A icon in the workgroup, a dialog showed up asking for user name and password, I type in the username and leave the password blank (comp A has only one user with blank password), but comp B still cannot access to comp A...

Here is some more information that may help

Both are using windows XP Pro SP2 with all latest updates.
comp A: using Norton Antivirus 2006, Norton Personal Firewall 2006
comp B: using Norton Antivirus 2005

Answer : I can see other computer, but others cannot see my computer

Windows XP Pro doesn't allow network access without a password. If you want it to work, you have to do this:

Run: gpedit.msc
Go to Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options
Click Accounts.. Choose 'Limit local account use of blank passwords to console login only'.
Select 'Disabled' and click OK.

Voila