To those in the Know!

I am a simple lad who knows enough about computers to get himself into trouble and I seek some wisdom and experience from anyone out there. 

Here is the issue:  I have just reformatted my Inspiron 6000 and loaded up all the drivers that I though I required.  Downloading most of the latest from the dell website using my product key.  Thing is I am unable to update the drivers on my Ethernet controller or PCI Modem.  My WiFi is working just dandy and to all intents and purposes so is everything else, oh except my DVD decoder went with the reformat and Im down one of those.  But that is another story..

My question is - what are the Ethernet controller and PCi Modem when they are at home why am I able to get internet through WiFi if they are not working?  Idid read on another threadsomthing about a sequence of installing these drivers?  is that so?

If not can anyone point me to a fix for this please

Cheers