sound echo`n problem

[Levidyllan]

i am experiencing a sound problem, to the fact that any music or voice sounds etc are used there is a bad echo that has attached itself to every sound. This also has attached itdelf to my modem dail tones. this is annoying can you help,
lap top
sis audio 7018 device/card.
xp pro

 

[Khayman]

you havn't got an open mic near the speakers have you?

if you have make sure you mute it from the main volume control