run "dmesg | grep agpgart".
If AGP support is compiled into the kernel then something should show up. If it is compiled as a module, make sure to "modprobe agpgart" before you run the dmesg stuff.
In order to use NVIDIA's AGP driver set NvAGP to "1".
Some other stuff to try:
-disable acpi for pci (append="pci=noacpi")
-disable apic (append="noapic")
-disable both (append="pci=noacpi noapic")
(the "append" entry should go into the /etc/lilo.conf, under the "image" tag of your current kernel - run "man lilo.conf" for more info on that file and remember to run "lilo" after you've changed the lilo.conf)
Please take a look at this post of yours:
I've already answered all of your questions there. For more details you'll have to read the HowTo's and/or man-pages.