Really, if you have proteus, I would definitly simulate first in Isis. It is very easy. You just need to load up the processor from the library and place it on your drawing sheet. Load up a logic probe and connect to port pin 0. That is all you need to do, no osc or power conns reqd. When you have done this, right click on the processor, and then left click. A sheet should appear where you can set up the osc freq etc, and set up the location of the hex file that you wish to use.
Press the play button, bottom right. All being well, the logic indicator should flash on/off. If this works then you have a hardware problem, if not, then check your code.
BTW, what country are you in?.