I have....

1 windows xp PC connecting to Internet via cable through Zyxel p600 modem and using zoneAlarm
1 windows xp Notebook connecting to internet via wireless and using zoneAlarm
1 Windows 7 laptop connecting to internet via wireless using windows firewall

Above 3 were perfectly able to file share and print under the name of WORKGROUP.

Today I have changed the wireless network connection name and password on my Zyxel modem.

My laptop and Notebook are able to see each other after I have put the new passwords.

But they can not see my PC. My PC can not see them either. ???

I am a bit lost...can you help me please? Thank you.