Hi,
Search and Download the TINY bootloader 19.
Program the 16f877 with the bootloader code, using another programmer.
Connect tx,rx pin through Max232 to the serial port of the computer. The osc crystal frequency is 4MHz. Connect reset switch to mclr pin. Set the com port on the bootloader software. If 16f877 device is detected by the loading software, you are in business. Now you can upload any hex file you want without a separate programmer.
Enjoy.
The best bootloader with free VB source code is Screamer V 1.6, I sware this is the best and the simplest I found. Ya, you first need simple programmer to load the bootloader and for that I am thankfull to FENG's MultiPIC programmer. good luck