Off hand can't remember that bios too much. There is a jumper on the mobo for cpu clock. One position is 100MHz for the durons and old 200 bus TBirds. The other is auto I believ and is for 266 and 333 bus chips. Make sure this is on Auto as it should have been anyway for your XP2000+.
There are also jumpers in a block that can be used to set the multiplier manually if you have issues in the bios. I think they go up to 18 or higher.
I am drawing a blank on the bios now an can't hook mine up right now to check, but if you don't see options in the bios to set the fsb or cpu host frequency and the multiplier, hit CTRL F1 to bring up the advanced chipset features. I wouldn't start higher than a 166 fsb on that mobo and work the multiplier up. Turn off the top performance as that will stress your ram. Later you can try turning that on once you find your max OC. I think that mobo can reach a 200 frequency setting, but I wouldn't wager it will do that. Start 166 and 11 or 12 multiplier and hopefully you can bump the multiplier up a setp at a time to 14 or even 15. Anyway, that's a start for you. if you have more problems let us know. if noone else can help, I'll set up my GA-7vax again and try it out. Lack of desk space has prevented it for a while. I was hoping to pop a mobile on that myself for a quiet 2.0GHz system soon anyway.
ABIT IS7, P4 2.6C, 512MB Corsair TwinX PC3200LL, Radeon 9800 Pro, Santa Cruz, TruePower 430watt