SET IT UP IN XP
Firstly, set up a workgroup by right-clicking My Computer > Properties > Computer Name and change the default Workgroup Name to something more meaningful in your household, also make the Computer Name recognisable, e.g. MainPC or IBMPC. The computer should reboot.
Now identify the folders/files you want to share and right-click them and select share and read or read/write access. A little hand should appear under those that are shared. Alternatively, drag the files you want to share to the Shared Documents folder (Public folder in Vista).
If you are sharing with a Vista machine, you may need to install the Link Layer Topology Discovery (LLTD) Responder on the XP machine click here
SET IT UP IN VISTA
Right-click Computer > Properties > Change Settings then change Computer Name and Workgroup Name. WinVista is slightly different click here
You may have to make Everyone appear in the Security Tab.
SHARE COMPLETE DRIVE
Right-click Computer > Manage > Storage > Disk Management then right-click the drive graphic > Properties > Security Tab > Edit > Add then type ‘Everyone’ (not the quotes) and below it select your preferences, e.g. Read or Full Control. Now Apply, OK, etc. to finish.
SHARE FOLDER OR FILE
Right-click the folder/file > Properties > Security Tab > Edit > Add then type ‘Everyone’ (not the quotes) and below it select your preferences, e.g. Read or Full Control. Now Apply, OK, etc. to finish.
Make sure in Control Panel > Network and Sharing Center you have Network Discovery, File Sharing and Public Folder Sharing set to ‘On’ and, if you‘re not using passwords set ’Password Protected Sharing to ‘Off’.
Repeat this on all PCs, use the same workgroup name but, of course, a different computer name.
To see or copy files, go to Start > My Network Places (Network in Vista) and the computers/folders/files should appear. Using Windows Explorer (in Start > All Programs > Accessories) drag them from one PC to the other.
Share a printer, here click here
Windows firewall is normally set to allow file and printer sharing but if you have a third-party firewall make sure that it allows access so that each machine can talk to the other(s).