pywin32 programming error on Win7 with shell.SHGetDesktopFolder, desktop.BindToObject, desktop.GetDisplayNameOf

[iMath]

thanks, I found out the reason： this question has no relationship with Win7 
or WinXP,but related to the users' system setting . 
GetDisplayNameOf() only gives the DISPLAY  name ,so the filename with or without extension acording to whether the user want to view files in the explorer with extension .
my settings is that filename with extension on WinXP but not on Win7,while os.listdir() returns filenames with extension on both of them ,this caused my problem here .
so anyone know how to fix my problem ? I mainly want to use shell.SHOpenFolderAndSelectItems() here.