AGP port stuck in PCI compatibility mode

I've got a Tyan Trinity KT motherboard based off the VIA KT-133 chipset, and I discovered the other day that my AGP port is stuck in PCI compatibility mode. I suspect I could squeeze more frames out of my GF2 if I could get the port into AGP mode, but I'm not sure what the problem is. I installed the latest Via 4-in-1 driver at Zorro's suggestion, and made sure that AGP is enabled in the BIOS. It seems to me that I had it working correctly when I was running Windows 2000, but it switched back over to PCI mode when I formatted and went to Windows XP a few months ago. Is there a setting in Windows or a utility that can throw the AGP slot into the correct mode?

have you checked the Windows Update page for updates?

Did you install 4-in-1's with XP?

I visit Windows Update frequently, and haven't run across any drivers or fixes. Not sure what you mean about installing 4-in-1's with XP. I formatted the HD, installed XP, and installed 4-in-1's, the latest Detonators, sound card drivers, etc. I just upgraded the 4 in 1 drivers last weekend to the ones that were released on 9/13.

okay... just making sure you got the 4-in-1 update when you installed XP...