Question : wiaManager = new WiaClass();        // create COM instance of WIA manager

Have been using:
wiaManager = new WiaClass();        // create COM instance of WIA manager
without problem for image acquisition in XP but in VISTA this fails with error:
Image Acquisition Failed: Retrieving the COM class factory for component with CLSID
Can you please suggest how to resolve this.

Answer : wiaManager = new WiaClass();        // create COM instance of WIA manager

Compile the project again in Windows Vista and Add the Windows Image acquisition  reference again as the windows xp and Vista Has seperate versions of WIA . this is the problem...