Question : How do I add a computer to my existing home network?

I have 4 computers on a wireless router. The main computer is hardwired to the router.  That computer and on laptop are on my home network and share files and a printer.  I have one computer that I can't figure out how to add it. I don't see my "network places" or "Add a Network Place" I see "create a network" but mine is already created.
What are the steps to add this computer to my home network?

Windows XP service pack 3 Dell

Answer : How do I add a computer to my existing home network?

Then try safe mode and log in as administrator. Steps 4 to 6