My website has an intro animation and a preloader loop that plays while the balance of the swf (exported as Flash 4) loads behind it. It was created on Mac using Flash 5.
It seems to work correctly (meaning that the swf starts playing right away) on Macintosh using either Netscape or IE, but on the PC, it only works using Netscape. In IE on a PC, the screen stays black while the entire swf is downloading, as if it doesn't see the intro or preloader loop at all.
Thanks for the help. Turns out that the object/embed conflict was in fact the problem. Why this problem only affected PC users using IE, I have no idea. But it's fixed now, and that's all I care about!