What is a network controller anyway?

Hello,
Problem:
I have one device in conflict: Network Controller

Cause:
I just reloaded windows xp on my dell latitude d620...I have installed all drivers or at least I thought I had.

Tried Solutions:
1. Under Network on the Dell support page, I installed the Boadcom Driver.
2. Under Communication, I installed the Conexant Driver
3. All other device drivers have been installed as well as well as the BIOS update and including the Chipset Driver.

There are many drivers on the page for d620's so I'm sure I'm overlooking one.

I'm hoping someone is familiar which which driver is needed for a Network Controller.

I am assuming the Broadcom driver is for the NIC and the Conexant is for the modem...what is a Network Controller anyway??

Thanks so much!
ekim