I have installed Fedora Core 5 to a PC that is part of a LAN. All of those PCs are connected to a switch which is connected to a modem/router through ethernet.
All of the other PCs are working fine with the m/r.
In this one I have made the IP settings:
IP address: 192.168.xxx.2
Mask: 255.255.255.0
Gateway: 192.168.xxx.1 (the m/r's IP)
DNS: (same as above)
(Fedora can also identify the MAC address of the ethernet card)

I have tested these settings with a live knoppix distro and worked fine.
But the Fedora system denies to ping the m/r's IP neither the other PCs' IPs (the other PCs can't ping it either).
This PC's LED on the switch is turned on, and I even tried to plug the PC directly to the m/r and work with DHCP but nothing worked either.

I can't figure out any solution.
What should I do?

Probably a stupid question but is the network card "active"?

Yeah...sorry about forgeting to mention it.
In the GNOME, where are the network settings, the network card is shown "active"

The only other thing I can think of is firewall, but that seems unlikely