One of the reasons that the command SLEEP will not work my be that you have not turned the Watchdog Timer ON.

I think there are two ways to turn the WDT on:

1. Some option in your programmer - i.e. one of the selection boxes along with CODE PROTECT, OSCILLATOR selection and so on?

2. By setting the CONFIGURATION register/word in you pic. You will need to read the Microchip Data Steet for the correct details.

Good luck

Bill Legge