need help to network home PCs to share files and printers,1 OS vista other X P?

Answer 1

How many PCs in total?

If just 2 - you only need a 'cross-wired' LAN UTP cable - they are readily available marked as 'suitable for networking 2 PCs' or similar.

You can connect a printer to one or both of the PCs.

If more than 2 machines and/or using Broadband, the easiest is by direct wired LAN UTP cable and a router (the Broadband modem may have a router in some models).

You can use SW Firewalls, but if you want a firewall in your router, then you will need more expensive equipment.

While many seem to prefer 'wireless networks', you will generally get faster LAN throughput speeds from LAN UTP cable rather than 'wireless' - and fewer security hassles - outsiders can use your Broadband connection unless you set up the security properly - such 'eavesdropping' is not as easily possible on direct wiring!

Recent laptops have a UTP connection, as should most newer desktops - if not you will need interface cards as appropriate.

Answer 2

Well, the basic set up is fairly easy. If you already have a router or have the computers connected. If not, step one, get a router (if you plan to have them using the internet together.) or use a switch (with no shared internet). Connect the computers to the router then Run the network setup wizard. That will let you setup both computers to the same workgroup name, add file and printer sharing to each (if not already added). and allow you to "share" files and printers.

To run the wizard on XP click on Control Panel and click the "Network Setup Wizard". I believe that will be the same on Vista.
Here is the Microsoft full tutorial for setting up a local network.
http://www.microsoft.com/technet/community/columns/cableguy/cg0604.mspx
It is almost identical for Vista.