Hi all, I can't open my webcam in matlab

This is the code i used

vid1 = videoinput('winvideo', 1, 'YUY2_320x240'); 
src1 = getselectedsource(vid1);
vid1.FramesPerTrigger = 1;
vid1.ReturnedColorspace = 'rgb';
start(vid1);
I = getdata(vid1);
stop(vid1);

when i run this it says 'Invalid ADAPTORNAME specified.' but i have downloaded the required adopter from Support Package Installer. in fact when i open imaqtool box in imformation tool box it shows 'dcam' as a installed adopter.

but in the hardware browser it doesn't show any cameras, when i write preview(webcam) in the command tab a window will come and close immediately.

Any ideas and comments would be greatly appreciated! Thank you, Nipun