System name connection problems

Hi Guys,

I am upgrading from system A to System B

System A called "JOHN".
IP Address = 10.10.10.1

PC Hosts file has 
JOHN 10.10.10.1

New System B called "JOHN2"
IP Address = 10.10.10.5

Went Live, and changed over w/end
changed System A from JOHN to JOHNOLD
and changed IP address from 10.10.10.1 to 10.10.10.7

Changed new System B to original system A
settings of JOHN and 10.10.10.1

ISSUES.

WIN98 clients attached OK, WINXP tried to attach
to old system despite me changing system name 
from JOHN to JOHNOLD and changing IP address??

( all expect 1 Win98 machine which did the same as XP?? )

I had to create new connection based on the IP address, 
and that was OK, but NOT if i used the system name.

What have i missed??
Something on the AS400?
Something on the PC's?

PS. i deleted the JOHN connection in Ops Nav, thought
if i recreated it, it would find the new box, 
but NO - it went back to the old one?




All/any ideas gratefully accepted?



Regards


Ian.