My Dell Inspiron 1545 make a noise

Hi,

i noted my Dell Inspiron 1545 <ADMIN NOTE: Service tag removed per privacy policy>  which i bout two weeks back, make a ( Teck ) sound every 10 min or so and it comes from the left side near the power plugin. i down't know if it is from power or left speaker or LCD, but i know it drive me crazy ... the OS is Windows 7.

Plz, help

Kamal S.