To answer your question
Overclocking is best done from the BIOS
When your computer boots up, it'll prompt you to hit F1 for boot priority, F2 for BIOS settings, and F10 for system restore (note that the F2 key for BIOS settings varies, it may be the DEL key or other F#s depending on how updated your BIOS is).
Normally you don't hit any buttons and windows or whatever your OS is loads automatically. This time you want to hit the F2 key or your BIOS equivalent
From the BIOS you want to navigate to the advanced tab. This is done by pressing the arrow keys.
Once you get to the advanced tab, you want to change the values for RAM and CPU reference clock.
Reference clock values are arbitrary. All you need to know is that by raising the reference clock value by 10%, you increase your stock frequency by a corresponding 10%.
I recommend OC the CPU and RAM by 11% each to start.
Once your done adjusting the values, hit F10 to exit and choose to save changes.
Then boot up your system and check for stability.
In the case that you can't modify the reference clock values (ie they are greyed out), then you'll have to resort to overclocking software.
Go for Ntunes this is easiest to use and doesn't require you to find your PLL and its largely self explanatory
Hope this helps