Hi Nuri, maybe this has already been answered, but I had the same problem on my first project. In fact, I had the it on the second too...... In my case, the crystal type (specified in the fuses) was incorrect for the actual type of unit I was using (i.e. HS, XT, RC). Soon as I figured it out, it worked great Dan D -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.