Nokia 3360 "NO SERVICE"

My 3360 problems started with the intermittent "no service" messages that would last for hours or days, and then suddenly the phone would work again. Sometimes after completing a call and pressing end, the phone would go to "no service" instead of "AT&T". Now it is stuck on "no service" all the time.

In another post someone suggested heating the power IC or all of the RF circuit ICs. (I presume this is to fix bad solder joints.) Is this a good idea? If it is, I would appreciate detailed instructions. If not, what do you suggest (other than getting a new phone)?