Networking XP to 7

[Quetzal59]

Hello

I use an XP wired tower connected to a printer, and have just acquired a Win 7 wireless PC tower. I would like to network both computers so that my Win 7 can access files currently on the XP machine. I have given file-sharing permissions on the XP machine to three folders that I would like the Win 7 to be able to pick up.

So, I have changed the Computer Name on the XP computer to WORKGROUP and restarted the computer, and I can see that the three folders are being offered as shared folders.

However, when I log-in to the Win 7 PC (which uses the same router as the XP machine) and click Computer | Network I can only see the joint router and my own Win 7 wireless PC tower. I cannot see the wired XP computer anywhere (it is switched on).

What am I doing wrong, please?

Thank you.