ok, for one thing. We'd need to know what motherboard your using. The bios is different on every manufacturors board. And I'm guessing you want to overclock your processor am I correct?
First you need to tell us a few things. Like what kind of processor?
Athlon XP 2600 doesn't help. Is it a Barton core, is it not?
Are you trying to raise the FSB = Front Side Bus from the processors common of 266mhz FSB (If it's not a barton), or 333mhz If it is a barton.
What type of heatsink and fan combination do you have for your processor?
What temperatures are you reading in celcius from the CPU?