If you are on a limited bandwidth plan, you may want to check which application is eating much bandwidth. In Microsoft Windows 7, you can check the Internet bandwidth usage by any particular program like email clients,Browsers or messengers. Here is how you can do it.
Click Start orb. In the search field, type “resource monitor” (or simply resource, without the quotation marks):
Resource Monitor will appear as a link on the top of the list. Simply hit Enter from keyboard. Resource Monitor will open. Click the Network tab, wait for few minutes to get all the applications those are dependent or using active Internet connection. You can see the application name, Bytes send and received per second and total Bytes per second. In the Listening Port list, you will see all the applications, those are dependent, but may not using active Internet connection at that moment: