How to overclock storebought pc?

i have an advent t9608 desktop pc which i bought in pc world a few years back and recently my friends mentioned overclocking which i was curious about so i've done a little research about it and how to do it, but i've been unable to find how to do it in my bios settings. i spoke to my friend about it and he said i wouldn't be able to overclock my pc because its a store bought pc. but i just wanted to check with you guys and see if it is possible or not.