I have an old HP 750C+ plotter I have been able to successfully load a driver on my Windows 7 64 bit computer and have plotted form it. I recently had some changes made to my computer and now cannot seem to install the plotter again. I can create PDF's and plot them with the plotter so I know windows is recognizing the plotter but auto cad will not. When i use the add-a- plotter wizard in auto cad ultimately it will ask me for a saved pcp or pc2 file or select plot to a port which is set up. My question is where can I find these files (PCP, or PC2) or is there another way to set up the plotter so I can plot through Auto Cad. I also know that I have to disable the windows driver signature upon system start up which I have done.