connectivity problem

i am having peer to peer network with win98
from last some time one client machine giving connectivity problem thats why i change the NIC
the card is 10/100mbps ,problem i am geting is it is very slow to respond when i use ping command
its reply but some time it give request timed out
and TTT value is 128 . same NIC i cheack on other
client machine its working fine. Can you plz try to solve my problem? ( the utp cabel is also fine)