network problem
 

I have a asus k8v deluxe motherbord with an onboard 3com gigabit network.

This works fine on internet, but on a local lan it's not working.
I have 4 pc's : each of them subnet 255.0.0.0 and the ip's are :
10.0.0.1 untill 10.0.0.4

When i startup my pc, I can ping all other pc's. The other pc's cannot ping me.
When i try to connect to a gaming server, the other pc's can see me joining the game, but I keep on seeing the load screen forever.
If I quit the game (I tried 3 kinds of games: mohaa,battlefield and callofduty) I cannot ping the other pc's anymore... I have to reboot.

I tried a switch and a hub, another networkcable, disabled auto-sensing and forced it to 10 Mbit half duplex, but nothing !!!

All help is welcome !!!!