David,

I went through almost the exact same scenario almost two years ago, and after losing a little too much hair I discovered that the problem lay in my epic programmer, the one that uses the printer port. Windows XP was playing havoc with the printer port on occasion. I upgraded to the newer USB programmer from MELABS, and have not had a hardware problems since. I still get the occassional software glitch, but as those are all self inflicted............. Anyway, perhaps someone a little closer to you might offer to program a 16f877 for you, and see if that works. I would be awfully suprised to learn that you have 6 defective chips and three defective development boards, my lab-x boards run continuously, and have never been a problem. The programmer seems to be the only thing that is common to all your problems, as you said you should be able to blink an led without any difficulty.

Jerry.