Workgroup connecting

I have a small network consisting of the laptop and two desktops with fixed
IP addresses. The workgroup worked perfectly.
Recently I wandered around and was connecting to web over wifi.
After my return I am unable to connect to the workgroup.
I get message List of the servers is not available, you are not authorised.
The rest of the worrkroup communicates but when the laptop is connected it
is not possible to open the workgroup as well.
Ping "sees" all the computers.
Net view with IP address gives correct answer, however with computer name it
gives error 53
Now I uninstalled 3rd party firewall and blocked Windows firewall.
It did not help.
Can somebody help me?