You haven’t said how far you’ve got with sharing, so here’s the complete procedure. This will make the computer a little less secure but it works because no passwords are used and everyone is allowed access.
1. SAME WORKGROUP (OPTIONAL)
Add your Windows 7 computer to the same workgroup as the XP machine. Control Panel > All Control Panel Items > System > Advanced System Settings (in the left pane) > Computer Name Tab > Change, type the Computer Name and Workgroup Name. > OK. The computer should restart.
2. FOLDER SHARING
First of all, go to Control Panel > All Control Panel Items > Network and Sharing Center > Change Advanced Sharing Settings. In the Home or Work profile, make sure you have Network Discovery, File and Printer Sharing and Public Folder Sharing all set to ‘On’ and Password Protected Sharing to ‘Off’. Don’t use HomeGroup.
To share a Windows 7 folder, right-click it > Properties > Sharing Tab > Advanced Sharing > Share this folder > Apply, OK > Close. An alternative way of sharing is to drag the folders you want to share to the Public folder.
As you don’t have Password Protected Sharing turned on, you have to change the security permissions on your folder(s) to allow Everyone access. Right-click the shared folder > Properties > Security Tab > Edit > Add and type ‘Everyone’ (not the quotes) into the box and OK. Tick the boxes next to the permissions you want to allow (e.g. Read or Write, etc.) then Apply > OK, etc. You may see some screens coming up with message 'An error occurred while applying ……..'. This is not unusual and can be ignored by clicking Continue.
Windows firewall is normally set to allow file and printer sharing but if you have a third-party firewall make sure file and printer sharing is enabled so that each machine can talk to the other(s). Don’t disable the Windows firewall if it’s the only one you’re running.