People can't hear me on Skype if I have my ear buds plugged in?

I own a Lenovo G500 and whenever I plug in ear buds my friends on Skype can't hear me. BUT whenever I have them unplugged they can hear me, but it does that infinite annoying echo. Can someone please help me? This has just started happening this week, before there wasn't ANY problem at all!

Buy earbuds that have a microphoone on them 20 bucks or less

It sounds like what's happening there's that the computer itself has speakers and a mic, but your earbuds obviously don't. When you plug them in, it disconnects the computer's speakers and mic, and transfers both functions to the headphone and mic plug. You have no mic plugged in, so they can't hear you.

Solution is to get a headset that can do both functions.