Ethernet controller missing dimension 2400

hi all,
for more than 2 weeks i been tryin to fix the ethernet problem. yellow dot in device manager shows besides ethernet controller. so i went to dell website for the network driver. i install it in my computer but the problem still remain same.
I have dell dimension 2400 desktop. after virus infection, my internet went off and i cn't connect to the internet. i format my computer and install a fresh xp pro. After installation i am missing several drivers in my computer .. like video, audio, intel chipset. so i install the drivers from the cd that come along with it when bought. ie, chipset, video, network, audio and modem...
everything install perfectly except the ethernet controller.. which keeps on showing a yellow dot, which i guess it means am missing network driver .. so i downloaded again from the CD and also from the dell website .. i still can't make it work ..i use RJ45 wire for the network ..
Can anyone shed some light on this thing .. ? i run the diagnostic from the dell cd today and it shows, on chip CPU------ unsupported test for BCM 440x.
helpme out i am so fraustrated.. and the dell CS isn't much of use.. Help me out .. plzzzzzzzzzz