old/new systems can't see each other

I just added three systems to a peer-to-peer and just have a few

important quirks. I'm not a novice but don't know the answer here.

All XP. Connected to a DSL modem/router. Router settings are default.

New 3 systems are default (get IP from DHCP etc). All on the same

workgroup. The three old systems can see each other but not see the

new ones. The new ones can see each other but not the old ones. There

are a couple network printers, the new ones can see but not the old

ones. When I say "see" I mean they don't show up in network

neighborhood. I can manually type in the name of a printer shared by

an old system and the new one can connect to it. All can print to the

printers even if they can't "see" them. I cannot force a new system to

connect to a shared folder on an old one, even when using IP address

and typing in the share name. So the one old one that acts as a file

server (just a shared disk) cannot be accessed by the new ones. They

can all get out to the internet. Two of the old ones are also on auto-

ip etc. One is fixed. Not sure if the guy who set it up had some

reason for that. No firewalls on systems.

Maybe the guy who set it up (who is not around now) made some

restrictions? One old system tries to boot directly into a particular

logon even though there are several logons and all have passwords.

(All systems have a JoBlow administrator logon and a Student limited

logon.) I've even eliminated the old logon it wants to use and created

a new one and it still tries to logon to the old name, or it gets hung

up trying. So maybe the guy who set it up locked some things down but

I'm not sure how.

Any ideas?

Thanks,

Tom