>boot
>     movlw     b'11101111'   ; sets all pin as inputs exept pin 3
>     tris      GPIO          ;turns led on
>     bsf       led

In your code, you are SETTING the led pin.  As you need to ground the cathode of the LED to light it, you should surely be CLEARING the pin at this point in order to turn the LED on, i.e. bcf led.

Cheers

Mike

 Greetings,

 my led won't lit up too. i'm using pic16c84. the code run well in
simulator,
 but not in circuit. is there any problem with my circuit ?

 ** please select variable width font. thank you. excuse my drawing :)
my first
 ascii circuit (and pic project too )

 configure to use RC osc, clear RB4 to sink current, thus turn LED on.
can see
 the PortB clear bit 4, TRISB is correct (all in mpsim). yet , in real
circuit
 it doesn't :(

 regards,
 ckchan