Help! LifeCam VX-5000 & Skype?

about 6 hours ago i purchased a LifeCam VX-2000 and it wouldn't work on Skype. I would see the person i was talking to but they couldn't see me so i took it back and got the LifeCam VX-5000 ...and it still doesn't work!!! :( I've tried Skype 4.2 & 5.1 with it ...how can i get it to work??? I'm currently using Skype 5.1 - It says on the box that it can go on Skype... please help.