Forcing task to end, doesn't work

Hello,
I am having a problem with my webcam, and any programs that use it. MSN messenger, and skype both freeze after a few minuites of use. I suspect the USB connection is faulty, but it is hard to be sure. In any case, after the webcam freezes, the program locks up. I can get the programs to disappear form my desktop, but I can't get the processes to end even using command prompt. Even the device manager freezes up when I go to reset the UBS port or disable the webcam. The computer is the unable to restart unless it is forced to with the physical power button. I have a few questions:
- Is there any (fairly simple) way from stopping the webcam from freezing?
- Is there a way to end the Skype or messenger procsses that I have so far missed?
- Has anyone else had this problem?
- Are there any settings I can change to avoid complete lock up if the webcam [or any similar USB device] is unexpectedly removed while in use?

Thanks for your help