Inspiron 15R-5521 (Late 2012) laptop, Windows 8.1, WEBCAM NOT WORKING :(

Hi Dell Users/Team, i recently bought Dell Inspiron 15R (5521, Late 2012) laptop with windows 8.
1) Few days everything was fine, but once i made a system recovery and updated to windoes 8.1 from 8 my webcam suddenly stops working. In device manager i can see Integrated webcam under imaging devices but when i open camera or skype it shows not connected.....

2) Also when i run Diagnostics it stops and don't proceed after "installing my Client step" with an error. 

please please please help me. my service tag is <private data deleted>.