There's no short answer to this: an entire book could be devoted to the subject. On a home network, where the printer is attached to one of the other computers, check that the other computer is both switched on and logged on. If the problem is on a mixed Windows XP/Vista network visit snipurl site, which is a step-by-step Microsoft Technet guide to sharing PCs and printers successfully between the two operating systems. On a domain-based network, if all you wish to do is find a networked printer from within Windows XP you can click Start, and then Search. Under 'What do you wish to search for', select 'Printers, Computers or People' and then click' A Printer on the Network'. This opens the Find Printers dialogue box where you can enter further search criteria. Having found a printer, connect to it by selecting the printer and opening the File menu, then click Connect.