There are no devices installed for the specified ADAPTORNAME

I was using the Matlab R2011b and intended to request the resource from the camera. The camera was well set up. 

Problem description:

>> OUT = imaqhwinfo 

OUT = 

    InstalledAdaptors: {'matrox'  'winvideo'}
        MATLABVersion: '7.13 (R2011b)'
          ToolboxName: 'Image Acquisition Toolbox'
       ToolboxVersion: '4.2 (R2011b)'

>> source.vid = videoinput('winvideo', 1,'YUY2_320x240');
Error using videoinput (line 228)
There are no devices installed for the specified ADAPTORNAME. See IMAQHWINFO.

 Solution:

>> imaqreset

>> vid = videoinput('winvideo', 1,'YUY2_320x240');
>> help imaqreset
 imaqreset Disconnect and delete all image acquisition objects.
 
     imaqreset deletes any image acquisition objects existing in 
     memory as well as unloads all adaptors loaded by the toolbox. As
     a result, the image acquisition hardware is reset.
 
     imaqreset is the image acquisition command that returns MATLAB to 
     the known state of having no image acquisition objects and no 
     loaded image acquisition adaptors.
 
     imaqreset will also force the toolbox to search for new hardware 
     that may have been installed while MATLAB was running.
 
     imaqreset should not be called from any of the callbacks of a
     VIDEOINPUT object such as the StartFcn or FramesAcquiredFcn.
 
     See also imaqhelp, imaqdevice/delete.

    Reference page in Help browser
       doc imaqreset