how do i disable hyper threading in my k42jk (core i3-350) asus laptop?

[behrooz_bb]

i have a asus laptop (k42jk). cpu is core i3-350 (2 cores, 4 threads). i noticed that in single thread applications maximum load of cpu is 25% because they use half of a core (1 thread). how to disable hyperthreading to use a whole core in single thread applications, as like as core 2 duo does ?