回複：write again with more info

yes, you are right, it is windows explorer "context" menu, such as when I selected a file, click right button of mouse, then pup up a lot of select list, among this list, there are several names of softwares I already deleted. How can I delete these items of softwares that deleted before, I guss it might be in the regedit, but where I don't know. Thanh you very much and have a good weekend.