Well, I finally got my Sound/Video/Nic working perfectly. If anyone else is having problems getting ther perhiperals to work on a P4P800 Deluxe running Debian 3.0 r2, hopefully this will help you with you out. (I spent way too long getting my things in working order)
Download kernel 2.6.6 or newer (http://www.kernel.org
When configuring the kernel, do the following.
NIC (Onboard 3Com Gigabit LOM (3c940):
---->Device Drivers/Networking Support/Ethernet (1000 Mbit), select
Marvell Yukon Chipset / SysKonnect SK-98xx Support
Sound (Onboard Soundmax/AC97/AD1985):
---->Device Drivers/Sound/Advanced LInux Architecture/
OSS Mixer API
OSS Seq API
Intel i8x0/MX440, SiS 7012, Ali 5455; NForce Audio; AMD768/8111
---->Video (GeForce FX 5200):
Device Drivers/Character Devices/
/dev/agpgart (AGP Support)
Compile, install, boot new kernel.
Download & Install nVidia driver from http://www.nvidia.com/object/linux_d..._1.0-5336.html