Actually the associative of the .swf files have changed from player to shockwave player. Try this if you are using Windows base system:
1) open up a folder and go to tools menu and choose Folder Options...
2) click on File Types tab and in the Registered file types list box scroll down until you find SWF file type
3) Choose SWF and in the Details section for SWF extension click the Change button and choose Flash player from the dialog box
4) or use Advanced button below the Change button