Please explain me WHY!

[Archangel]

I am using PIC16F690.
I am wondering why when I use the following program:
"
intcon=0
cm1con0=0
cm2con0=0
ansel=0
anselh=0
trisc=0
portc=0
define OSC 4
option_reg = %00001000

main:
high portC.0
high portC.1
high portC.2
high portC.3
pause 1000
low portc.0
low portc.1
low portc.2
low portc.3
pause 1000
goto main
"
All leds connected to PORTC work as expected.
AND why they don't work when I use the following code:
"
intcon=0
cm1con0=0
cm2con0=0
ansel=0
anselh=0
trisc=0
portc=0
define OSC 4
option_reg = %00001000

main:
high portC
pause 1000
low portC
pause 1000
goto main
"

Can't tell you why, except <b>maybe </b>it's not supposed too, You CAN do this:
PortC = 255
pause 1000
PortC = 0

Put ADCON0 = 0 in to disable the A/D converters too