SWF and HTML files won't play unless flash is installed

[layerburn]

My .swf and.html files won't play even with latest Flash player installed (flash player 9). The html will play if right clicked and internet explorer is selected manually, but not on its own. Both files will play when on a computer with Flash installed. I finished the project and published them using Flash 8, what's going on? I didn't see anything in the release notes. Anyone have an idea or had this problem? Thanks!

[fastwarp]

I have same problem. Could it be IE 8 ? Funny it ( .swf) plays in
IE8 but not the installed shockwave or Flash player. Yes when I install
Flash 8 or above the .swf opens. This (these) PC have deepfreeze
installed, maybe that is a factor.