Mudokon;
You have 2 options, if you want to try overclocking, and you don't know what your doing. The first is to try to experiment with various settings, and hope for the best. If you go to far, the system won't reboot, and you just kill the power by unplugging the power supply, or reset the cmos, by removing the battery and using the jumper according to the manual
That will bring you back to the bios settings, so you can make corrections.
Or; did you install the overclocking software that came on the Asus cd(Ai suite)? It's not the best option, but I think it would be safer to use.
I used it for a short time, after I built the system, and got up to 2660mhz. Btw what bios version are you using?
You should go to the Asus site and download the 0309 version, it gives you more of a range, for overclocking
I'm sorry I couldn't help more, but at this point, I'm just happy that my system runs well @ stock settings. Maybe in the future, but I'm not a gamer, and it's fast enough the way it is.
Good luck!