18f452 Problems

[mister_e]

what about if you place the following lines at the top of your code

@ __CONFIG _CONFIG1H, _OSCS_OFF_1H & _HS_OSC_1H
    ' Oscillator switch OFF
    ' Use HS oscillator (20MHZ here)
    '
@ __CONFIG _CONFIG2L, _BOR_ON_2L & _PWRT_ON_2L & _BORV_45_2L
    ' Brown out reset ON @ 4.5Volts
    ' Power-up timer ON
    '
@ __CONFIG _CONFIG2H, _WDT_ON_2H 
    ' Watch dog timer ON
    '
@ __CONFIG _CONFIG4L, _STVR_ON_4L & _LVP_OFF_4L & _DEBUG_OFF_4L
    ' Stack over/underflow ON
    ' Low Voltage programming OFF
    ' Background debugger OFF
    
DEFINE OSC 20

Be sure you correctly disable analog or multiplexed stuff on the I/O you're using for your LED.