Windows vista File Sharing

Hi! Im new to windows vista, I have 3 computers connected to a router then to a switch, my 3 computer can access the internet and the ip address of my pc uses dhcp that came from my router pc1 is 192.168.0.2 with subnet 255.255.255.0 and pc2 is 192.168.0.3 with subnet 255.255.255.0 and pc3 is 192.168.0.17 with subnet 255.255.255.0 my problem is that i can't access the public folder on my pc1 and pc2 cant access the shared folders on pc3 but pc3 can access pc1 and pc2 and one thing i noticed is that when i tried to ping test pc 3 on the pc itself the result is request time out but it is connected to my network. Can anyone help me on this. Thks in advance