Hello Jerry

Make sure your other 3 computers are all on the same subnet...255.255.255.0
and also check to see if the 3 computers you can not ping are not blocking
the ping or any ICMP packets. Look at Windows firewall and or any other
firewall you may have installed that may be blocking ICMP packets. You can
also check that IPsec is not filtering out ICMP packets.

Question is your ADSL modem really a dsl router ? If so connect to the
routers firmware 192.168.1.1 and configure it for a home network so it allows
other computers from your internal LAN to pass through.

No need to worry. Takes a bit of time. All in 0's and 1's and you should
have your computers talking to each other like long lost friends.

Hi
Might be Software Firewall blocking Local Traffic?
Jack (MVP-Networking).

I would check the Firewall first. This search result may help,

How to enable ping in Windows FirewallBy default, Windows Firewall disable ICMP. That blocks ping to the computer. ... Open Windows Firewall by going to Control Panel or the properties of the ...
     www.howtonetworking.com/Windows/xpicf5.htm  

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net 
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com 
 may network have 4 address that is
 192.168.1.1 belong to a adsl modem
 192.168.1.2 belong to a pc
 192.168.1.3 belong to a pc
 192.168.1.5 belong to a pc
 i only can ping one address that is 192.168.1.1 & all the address i cannot
 ping. i also cannot ping my own pc.
 please help me to solve the problem.
 i can see info in a pc on the network & file and printer sharing but i use
 one program that need to ping to other pc for sharing info.
 please help me to solve the ping problem.

 my email are jerryho81@yahoo.com or jerryho8@streamyx.com