Ah. A similar setup as mine. Do you know your way in BIOs? If no, start up your computer and keep pressing the DEL button.
Your RAM will limit you to overclock because it's a 667Mhz RAM.
It is recommended that you manually set your own vcore/CPU voltage. default is 1.350 vcore and the top in our boards are 2.0vcore, so be careful about that.
C1E in Advance options will reduce your clock when you're idle. It's a power saving feature and I like to leave mine on. So, if you don't like your multiplier dropping, just turn C1E off.
When you're in BIOs, go into MIT (Bottom left option). You will see the following. NOTE that you will not have the RAM timing feature. I will tell you that later.
From the picture, ENABLE CPU Clock Host Control. Set PCI Express Frequency to 100Mhz.
Now, head to the bottom and you will see the voltage control.
Make System Voltage Control from Auto to Manual. Set CPU Voltage Control to 1.3 vcore. DO NOT set it to 2.0vcore like in that picture.
From here, go back up and you'll see CPU Host Frquency: 266. Since this is your first time overclocking, Change 266 to 270. Head back out, save your settings and boot onto desktop.
When you raise the CPU Host Frequency, your RAM speed will go higher and at a point, it will not start your PC. You can divide by using the System Memory Multiplier.
I hope I didn't leave anything out.
How to enable RAM timings: Before you enter MIT, press CTRL + F1.
If your computer does not start up after overclocking everything. Go look at your motherboard. Find a circular silver battery and remove it. Let your motherboard sit there without the battery for a minute. After thatm put the battery back on and boot.
With a DDR2 800 RAM, I can hit 3.0Ghz with 1.28 vcore. So, it is possible to have a higher Ghz and lower vcore. My RAM is divided by 2.0.