I just rebuilt my PC with a Gigabyte EP45-UD3P motherboard. My intent was to also just wipe the system drive and start with a fresh XP load. Well the PC is up and running fine without wiping the system drive yet. When I boot from my XP disc to attempt to wipe the drive and reload the OS, it goes through the normal process of grabbing the drivers it needs from the disk, but when it tries to proceed, the blue screens and says there is an error with pci.sys. Weird.
It recommends updating the BIOS to the latest, which I did, but that didn't make any difference.
More about :pci sys problem installing gigabyte ep45 ud3p
You may need newer drivers than what's on the XP install disc. Check the Gigabyte website to see if they've got anything on this issue.
You can make your own updated ("slipstream") XP boot/install disc by using a free program called nlite.
Had same exact issue with same MOBO. I can personally attest to the success of using the nLite tool for slipstreaming XP. Do as the wizard guides you from within the tool and you'll be fine. I did not add any additional drivers nor did I make any radical exclusions to the slipstream; just Windows XP install disk and Service Pack2.. that's it and it flew by the error into the format routine as you expect and hope for!