Network not found

At home I have a small LAN connecting four Win98 laptops through a
switch/HUB. All four are in the same workgroup and the TCP/IP settings are
set on auto.
Yesterday I took one laptop ( and went to an Internet Cafe where I had no
problems connecting to their network. All I had to do was to connect their
cable to my PCMCIA Ethernet card and I was connected.
The problem started when I went home and reconnected the laptop to the LAN.
None of the other laptops saw this laptop nor did it see any of the others.
When I tried "Release all" and "Renew all" (Start-Run-winipcfg), I got a
DHCP error message. After turning the laptop on and off a few times and
changing "Primary Network Logon" back and forth, restarting the laptop it
finally appeared again.
How can I easily go from network to network without going through all this?
Thanks,
AJS