Ethernet card is not recognize in system profiler

[dom17]

Hello, my configuration is

 

Dell XPS 420

core 2 duo E6850 3GHZ

NVIDIA 8600 GTS

 

I made the installation on a externel USB Harddisk. Everething is working fine with Kalyway 10.5.2 but no sound and onboard Ethernet.

 

I'm planning to buy a USB or firewire sound card because I'm a musician.

 

But the problem is about internet: I have installed a cheap ethernet card but leopard seem not able to detect it when I restart. Is there an easy way to install it.

 

I've tried tow model:

 

1: D-link: DFE-530TX 10/100Mbps

2: generic realteck: encore ENL832-TX-RENT 10/100Mbps (RTL8139D on the chipset)

 

This problem is the only thing it made I stay with Vista.

 

Thank You !