Starting over might not be a bad idea but regardless you always need to make sure you have the correct drivers installed.
Motherboard chipset drivers: go to the motherboard manufacturers support site and grab the latest chipset drivers for your model and for XP.
Ethernet driver: Assuming you're using the onboard one, this is probably be included in the chipset drivers. If not you can grab it off the motherboard manufacturer site.
Same goes for onboard audio drivers.
Videocard drivers
Update XP with service pack 2 if it's not already on that copy of XP. Or just do all the updates off the microsoft site.
Do all this before you attempt to install any programs.