I cannot reach other PC in LAN, but can reach Internet?

[Lev]

I have a small LAN with 4-port ADSL Modem Router and 3 computers under
WinXP.
There was a crash on a computer. After recovering I cannot connect to the
modem, I received next message - "Purging the DNS Resolver cache". After
installing SP1 I can connect to Internet, but cannot reach other 2 computers
in my LAN.
Can somebody explain me why? Internet and 2 computers are connected to my
computer through the same cable and the same device - 4-port ADSL Modem
Router.
Thank in advance
Lev

 

[Lev]

Thanks to all! I have found this by myself. It was simply - in ZoneAlarm for
Network was filled Internet Zone. It should be Trusted Zone!
Thank
Lev