Skype calls break up after couple minutes. While I can still hear the person I am calling, he only hears very much noise and the call is breaking up.

There is a intermittent problem in the remote phone, main base, or the phone lead from the base to the phone jack. Replace the phone line, hopefully that will correct the problem.

it depends on ur netspeed

This is probably because dial tones and ringing tones are part of an archaic system. Your cell phone still makes these noises as a courtesy, and you hear the dial tones/ringing tones when you make regular calls because your phone is communicating with the standard phone system.

Try updating your OS.

I suggest you download the latest version of Skype from :-
www.skype.com

The performance of Skype is affected by the bandwidth available from your ISP. The video image your are sending and receiving occupy a large part of the information transmitted over the Internet, therefore make sure the video image setting is at a resolution of 320X240 (e-mail size) and if this is still affecting the audio quality to the other person (ie. the voice breaks up) and the video image then switch the video camera off and if sound and video image from the other party is also affecting you, then also get them to switch off their video camera.
Also check the Video and Microphone settings in Skype - Tools - Options etc. Check the correct video camera and microphone has been selected.

You can only use the webcam with one device at a time? If you are sure the webcam is working properly shut down the software specifically for your webcam.

Log into Skype as normal.

Do you see the video call options in Skype?
In Skype you can check what you see in the following path?
Tools/ Options/ Video Settings/ Camera
Is you webcam listed if not link it using the option here.

go to default all setting