Noise on audio on call inbound - outbound

I have trouble making calls or recive calls. I listen to static noise in the background of the so-called online. My hardware is: Dell Vostro Computer Intel Core 2 Duo 1,8 Ghz, 2 Gb RAM, HD 80 SATA, 3Com Ethernet, Wildcard TE110P. Please helpme for solution this problem. Thanks.

Are there internal calls or through an a phone provider ? IP lines or hard lines ? What kind of phones ?