First, if you have an alternative slot, go into device manager, remove the card from there, close the machine down, remove the card and reinstall in the new slot. Try again! (It may be an IRQ conflict).
Alternatively, you could go to click here and download the latest available drivers, but note you will need to find out which series you have, as there are three alternatives.
I am surprised you are having trouble with this, as Realtek cards are normally trouble free on installation. In fact, I use them myself on a W2K based machine.
One other thing that springs to mind, don't connect the card to anything other than the motherboard. All connection and configuration to the network, should be carried out after a successful installation has been achieved.