Win98 Networking

Hello,

I have 3 pc’s running win98. They are all connected via a 3 com 100mbits hub.
My problem is that PC1 and 2 can access a share on PC3 in 1 second, however PC3 takes 5 minutes (times out at times and freezes the computer) when it tries to access shares on both PC1 and 2. Anyone have any ideas before I change the Ethernet card on PC3?