network adaptor or configuration?

Hi, I have two computers running win xp pro and am trying to set up
simple file sharing (fat32). On each computer I can ping its name
but not the other address. I get a request timed out message which
may indicate there is a network. OTOH, when rebooting one computer1
the network adaptor shows up in devices with a yellow exclamation !

I reinstall and it reads enabled but no network is established. So
I'm wondering if this is some kind of IRQ conflict between the bios
and the OS or a bad Nic card. I don't see a good reason to buy a
new Nic card if it is some type of channel conflict. The IRQ is 10
and I not sure how to find out if it is shared by several devices.

Regards,
Stephen