YM Voice Problem

Dear friends

I use YM 7 to call PC to PC. But the problem is I can’t hear the voice and vice versa. I installed true speech. But still have the same problem. The gtalk works fine with me. I tried to install different versions of YM. But nothing works . I use Fujitsu Laptop FMV 7000na2. Windows XP professional. Please healp :-)

..i trying to call my friends but the problems is they can’t hear and see my calling info.with their screen,and also the same as on my screen i can’t receive their calling i dont see on my screen and i cant see the info that they are calling me!! so what might be the problems of my acer laptop?! please helps me about this!! thankz