When files stored on another computer can't be accessed via the network, there can be a number of potential solutions. Most obviously, check that the other computer is turned on and connected to the network. Check, too, that the folder or disk you want to see is still shared - fGr Windows XP, find it in Explorer, right click and choose' Sharing and Security.'

When some of the computers on a network use Windows Vista, things are a little more complicated. While XP Home lets just about anyone see shared folders, Vista usually requires a username and password. To stop this, open the Vista computer's Network and Sharing Center and disable the 'Password protected sharing' option. You can now right-click a folder, select Share and make it visible to everyone on
the network.

Vista's improved security also offers another potential problem with networking. Firstly, in order to see other computers and share files both 'Discovery' and' File Sharing' must be enabled in the Network and Sharing Center. Vista also classifies every network as public or private, and file sharing is only available on private networks. In the Network and Sharing Center, click the Customize link to the right of the network, and you can choose whether it's public or private - any home network should be private.

Finally, to make sure computers show up when you browse the network, they all need to be assigned to the same workgroup. This can be any short name, but it must be the same on every PC. In Windows XP, open the Control Panel, double click on System and then click the Computer Name tab. Vista users should go to the Network and Sharing Centre, click the arrow to the right of Network Discovery
and use the 'Change settings' link next to the workgroup name.