I moved this topic to the Hardware forum,
You give no indication of Operating systems your using
So I will assume it's a Hardware problem
Mind you, you don't give no indication of what Hardware your using
As eg.. Router make/model
Please note, as general check
Ensure that ALL firewalls are disabled when trying to setup your network, this is especially important in software firewalls such as Nortons IS
Ensure your computers on the network are on the EXACT workgroup>>Don't guess, double check
Share a folder, this should be done by default when using the Network Wizard, but set one up manually if unsure
Don't share the whole volume unless necessary