Archangel,

Thank you. I read section 11.2. So, I am going to instal a 10K pot and connect its wiper to RA3 to serve as Vref+. I will ground RA2 and to serve as Vref-. The low pin of the pot will be grounded and the top pin will be connected to +5VDC. I will change the line ADCON1 = 00000000 to be ADCON1 = 00001000

Does this make sense?