All right guys!!! i think i've finally made the web cam work!!!
am using Asus n61jv, i bought it since 2010 but i've been suffuring from this problem for three years. But thanx to god i've finally made it work every time i need it.. In one word this problem is a mechanical problem caused by the manufacture and it has nothing with other softwares or updates.. what i did was so simple, i've squeezed the camera before running the program (in my case i've run lifeframe3 and smartlogon manager) and keep squeezing untill the camera start to show and then leave it, for most of cases it didn't stop by it's own, but if it did then simply close the program, squeeze and run. i now it's sound annoying but it is better than no camera at all.
I hope this will work for you all and good luck