Catcher

Hi, im new to this forum and not sure how it works so here goes.... I have a bog standard logitech webcam messenger and windows xp with service pack 2 and the only way i can use my webcam is by being off line, whenever im online if i click on my webcam icon to start it up the whole computer freezes and nothing responds?? anything i can do about it? Ive uninstalled everything once and reinstalled drivers but exactly same problem as before.