<< Heh, the grass is always greener on the other side! So many people wish for unlocked CPU's, and you are looking to lock yours! Personally, I'd leave it alone (there will come a time when you'll value the unlocked CPU). It should be possible to lock it by cutting the bridge(s) necessary, however I am not very familiar with how to do this. >>
Supposedly, you use two needles hooked up to a relatively high current DC power supply and touch two points. The middle should flash and burn out. I saw this on a website describing L7(or L6) to fool the motherboard on supported voltage. I really don't feel like frying the processor though, cuz I'd have to buy a new one even though I don't need a new one.