In addition to making sure all computers are in the same Workgroup, avoid Homegroups as they are not compatible with downlevel client machines like XP.
And
enable NetBIOS over TCP/IP in the properties of IPv4, under the WINS tab, within the properties of your network interface card.
type
services.msc
into the search box and hit enter
confirm that the following services are started, consider setting the startup type to automatic
Computer Browser
Function Discovery Provider Host
Function Discovery Resource Publication
Network Connections
Network List Service
Network Location Awareness
Network Store Interface Service
Server
SSDP Discovery
TCP/IP NetBIOS Helper
Workstation
And if you are receiving an error message when attempting to...