Wireless Networking

i am unable to connect my pc together with my network. i
have three LAN pc an one WLAN laptop. I have a cable
modem that connects to my router than all the pc's
connect the the router. All the pc's have an internet
connection but none of them can access the workgroup.
How do i share printers hard drives and other files and
devices over my home network. i have run the windows home
network setup wizard but that did nothing. I was told by
others that i will need to setup my network manually. i
am un sure on how to do that so i was wondering if
somebody new how.

My Desktops use Windows XP Home
My Laptop uses Windows XP Pro