Multi stopped working past 12.5 on NF7-S

Ok, im stuck and need some help. My mobo wont let me select multi's higher than 12.5. It used to do it, and I've not really changed anything . Its an Abit NF7-S v2.0 and it should be able to use all the multipliers, I was using 15 and 16 the other day no problem. Anyone got any ideas? Im using a factory unlocked Barton 2500+ and I just reflashed the BIOS. Everytime I go from 12.5 to 13 the mobo wont POST, even with low bus speed. Can anyone help?

Right now I have 12.5 x 188, 2362MHz. and I have run at 15x188 so its not that the cpu cant take the speed and its not the cooling as im using a custom phasechange setup.

Thanks.

Try flashin back to your old bios, or a different one.

Multi's stopped working on original BIOS, I reflashed the original and they still didnt work (original being 21). I just flashed with 18 and multi didnt work with that either.