I'm not that experienced enough to resolve this issue, especially as the code is assembly and not PicBASIC pro, but looking at the schematic it shows the values for the crystal capacitors being 68pf. If you look at the datasheet for then 16F84 ( http://ww1.microchip.com/downloads/e...Doc/30430c.pdf ) it states in table 8-1 that for a 4 MHz crystal the preferred values are 15pf - 33pf. Maybe having the higher values which are suitable for Khz timing xtals does not suit the PIC and its not actually running ?