Sony Cybershot sticky shutter button

hi all,
i have a sony cybershot dsc-h7 which seems to have developed a faulty shutter button.
the focus will often briefly lock when the button is half-pressed,then go to refocus again instead of holding the focus gained.i need to often jump on the button to actually take the picture.(it does this in all modes)
sometimes its fine,but 3/4 of the time it acts up.
it certainly didnt used to do this,and of course it is literally a month out of the year's warranty.
does anyone know if it is easy enough to strip the button ? presumably by taking the camera apart,as i would guess it is maybe gunk stuck in the mechanism.
any help much appreciated,
cheers,
col