Velly intelesting!
If someone called me on Skype, I'd get the usual ringing noise, and a box on the screen to accept or reject the call. Clicking on "Accept" would answer so the caller and I could hear each other, but the ringing noise would continue in my speakers so I couldn't hear what they said.
Within a minute or so in a call, the CPU use meter would reach 100% and all would come to a stop. Skype would eventually report "Your computer is very slow". It had by then long since ceased to provide communication.
I uninstalled it, and installed the old version that was still sitting in my downloads box. Guess what - it's all working absolutely fine now!