We have three computers on a network all running xp. Two are wireless. The two wireless can talk to each other and share, but the wired one can't talk or share with the other two. All can get one the internet. I want the wired one to beable to share files and printer. HOW!

Is the wired one on the same workgroup? Right click My Computer, properties, computer name tab, to check the workgroup name.

We have three computers on a network all running xp. Two are wireless. The two wireless can talk to each other and share, but the wired one can't talk or share with the other two. All can get one the internet. I want the wired one to beable to share files and printer. HOW!
Have you checked your firewall settings?
Allowed permissions for other computers to access your shared folder?
Can you ping the other computer?