David,

You had mentioned that the configurations were a mystery to you. Why dont you post the configurations settings that you've been using. If you had it working once, then the code would appear to be ok. Next items to check are Configurations and hardware..and you seem to have gone through plenty of scenario's with the hardware.

I've had problems where a simple config setting has driven me nuts, and once the setting was changed it worked like a charm. If you have MCLR set as RESET then you must have a resistor tied to +5v. I havent seen any talk of this other than mister_e's post. Write up a list of what your currently using, I think it may be beneficial. Im learning aswell, my knowledge with pic chips is very limited. If you think this may be irrelevent, I apologize for wasting your time.

Good luck to you
James