my realtek sound does not work since updating to comodo fireall + defence

my realtek does not work since updateing to comodo + defence. because it is not digitly signed it worked very well before with my windows xp . I need my sound back. will i have to turn of the defence is there a way to solve this problem
:-[My realtek sound was not working due to my own fault in not turning my sound on from rear of surround sound i normly turn it on just after turning on the computor. i forgot to turn it on this time. and i thought comodo had turned my sound off because it was not digitly signed. and i was so fed up i deactivated the defence and undid the tick for trusted application digitly signed and rebooted my computor I system restored the computor to an earlier time. But luckily i undid the system restore point and got comodo back as when i updated I restored the defence the way it was and every thing is working as it should. :SMLR