I have just put together my new build. Installed XPpro64 and now am trying to get all drivers/devices working. I have updated BIOS and downloaded the newest 780i drivers. Initially I ran into a problem with the audio but resolved that through a Microsoft Hotfix.  
 
My problem now is that under Device Manager I am showing 4 devices not working.
"Network Controller"
"Other PCI Bridge Device"
"Other PCI Bridge Device"
"SM Bus Controller"
 
What drivers am I needing/missing?
 
I do have a Linksys PCI Wireless G card installed but have not been able to install drivers for it yet. Also, there seems to be no Ethernet devices listed in the network connections panel.
 
ORDER I INSTALLED:
- Firm ware update to HDD
- Partitioned HDD
- Installed Win XP Pro 64bit
- Updated 780i BIOS (NF78_P03.bin)
- Installed 780i drivers (nForce 9.46)
- Installed 8800gts drivers (169.28)
- Installed Hotfix for Audio found at (http://support.microsoft.com/?kbid=901105)
- Installed 780i audio drivers (WDM_R185)
 
SYSTEM:
CPU: Q6600
MB: EVGA 780i
GPU: (2x) EVGA 800gts 512
MEM: (4x) 2GB GSkill PC8000
NIC: Linksys WMP54Gv4

all them devices listed SHOULD be taken care by the chipset drivers (the nforce platform drivers).  did you get the right version (64bit?)..  
 
Have you tried to re-install the chipset drivers??  

^^^ Exactly. nvidia uses unified drivers which does everything from audio to chipsets. Install 'em all at once. EXCEPT their firewall which is garbage.
 
BTW, do not use windows to flash bios. You're asking for trouble. Burn the bin file to a cd/dvd & boot up, then press ALT F2 I think to run the onboard flash program. It'll auto fine the file on disk.