OK, are you using ICSP or the ZIF socket?
Can you verify the connectons between the 5 pins on the chip and the programmer or is it some integrated thing?
Have you another chip? (Happy to post you one, I have many, if you want one programmed with the .hex then I can do that too)
Text below is from a quick lash up on a breadboard:
Device ID is unavailable for this device
*****************************************************
Connecting to MPLAB PICkit 3...
Currently loaded firmware on PICkit 3
Firmware Suite Version.....01.50.04 *
Firmware type..............Midrange
Target device was not found (could not detect target voltage VDD). You must connect to a target device to use PICkit 3.
*****************************************************
At this point I enabled "Power Target Circuit from tool"
Connecting to MPLAB PICkit 3...
Currently loaded firmware on PICkit 3
Firmware Suite Version.....01.55.01
Firmware type..............Midrange
Programmer to target power is enabled - VDD = 5.000000 volts.
Target device PIC16F876A found.
Device Revision ID = 8
Reading...
The following memory area(s) will be read:
program memory: start address = 0x0, end address = 0x1fff
configuration memory
EEData memory
User Id Memory
Read complete
So, with a genuine PICKit3 and a very rough lashup it works as expected and would seem to be the same procedure that you've followed so I suspect your hardware config and/or chip is at fault rather than anything you've done wrong in the setup, has it ever worked?