All you need to set is ADCON0.7 = 1 for right justification. PBP will
handle channel select bits and ADON.

Try this.
Code:
DEFINE ADC_BITS 10 
DEFINE ADC_CLOCK 3 
DEFINE ADC_SAMPLEUS 50 
number VAR word

CMCON = 7          ' Comparators off
ANSEL = %00000001  ' GPIO.0 A/D in, rest digital
ADCON0.7 = 1       ' Right justify for 10-bit
TRISIO = %00000001 ' GPIO.0 = input, rest outputs

    Pause 100

Loop:
    ADCIN 0, number ' (0-1023)
    IF (number > 0) AND (number < 400) Then
      GPIO 1=1
      GPIO.2=0
      GPIO.4=0
    EndIF
    IF (number > 401) AND (number < 800) Then
      GPIO.1=0
      GPIO.2=1
      GPIO.4=0
    EndIF
    IF (number > 801) AND (number < 1024) Then
      GPIO.1=0
      GPIO.2=0
      GPIO.4=1
    EndIF
    number = 0
    GoTo loop
    
    End
Assuming you have your config fuse options & oscillator setup
properly, this should work.

You can find several more 12F675 A/D examples here;
http://www.microengineeringlabs.com/...ples.htm#x4pbp