Upping the Vcore

[ps2cho]

Hey iv got an ECS K7VTA3 Ver8 Mobo /w AMD ATHLON XP 2000+

now when i get it above 2000 my comp instantly restarts before it hits the windows screen

now im guessing /w help from others that i need bring my vcore up from stock

now there isnt any options in the BIOS to do it =*( is their any other methods at all ??