Hi:
If you installed Windows XP SP2 or SP3, please go to the device manager and click on the network device needing drivers.
It will be listed with a little yellow ? mark.
Click on that device and click on the Details tab.
Post the hardware ID string of characters that begins with the PCI/VEN
The PC can have either an Intel or Broadcom network adapter, so I need the hardware ID to post the right driver for it.
Also according to the motherboard model you posted below is the link to the support and driver page to the PC that uses that motherboard.