I have Widnows Vista installed on my system and recently installed QT 4.5.2 ON my system

I am totally a newbie and was running some examples when i found out that whenever I run apps with QpushButton added using Qdeveloper by dragging and ddropping
it doesnt work

I add slot to it but on running app, clicking on the Push button doesnt work, though pressing the enter button does the job but no Mouse press works. Pls help and telll where i am lagging

The examples that i used which involved declaring and then connecting via connect worked fine but where am i going wrong graphically

please help
thanks in advance