(adsbygoogle = window.adsbygoogle || []).push({}); Title basically describes it, is this possible. If so could somone please explain to me what to do! Thanks

Yeah it depends on what device you have, and if your device supports the kernel you're changing to.
P.S. I just used odin to change my kernal for my Samsung Galaxy Player 5.0 not too long ago

Im on the galaxy s2, i was wondering if i would have to use the original kernel then the insecure one

Iv got a galaxy note and i used odin to downgrade my phone (installed stock rooted modem, rom and kerenl) because my phone came upgraded to the latest frmware. Galaxy Notes come with an unlocked bootloader as stock.
What do you want to acheive? Root? CWM? Etc...
and what version of androi do you have?