“Cannot double click on desktop or explo

I am running win98se which is going normail before.. but i dont know.., suddenly i cannot double click the icon on the desktop or in explorer so i have to right click to open every file in windows. Well.. of course I’ve checked the desktop setting, and it seems fine, nothing changed. I assumed someone changed from the registry. Now.. if my assumption is correct, do you have any idea which key in registry do i have to checked.

Bye