sound problem when I'm using yahoo msgr or skype for the user at the other end !

Hi,
I have the windows XP operating system on the computer.
Whenever I’m using yahoo messenger and skype to do voice chat, I can hardly speak to the other person.
for me it is ok to listen but the other person gets a disturbance and then the call is dropped or has to be ended. This happens continously and this happens to all the users speaking to me on yahoo messenger and skype, so seems like the problem on my computer....
pls can you help me with the same...

Best Regards,

R