[Sentry]

Well, since Microsoft no longer offers any software updates for Win98, you may not want to bother troubleshooting problems with it. Any users who want to have their computers compatible with current software and media will sooner or later be forced to shell out money for a newer OS, which is of course the point behind Microsoft no longer offering updates for '98. If I were you, honestly, I'd just make sure everything works fine with Win2k, Vista, and Mac OS X and leave it at that. When it comes to media files, if it works well with Win2k it should work well with XP as well, and if it works well with OS X it should do ok in Linux also (assuming said Linux users have VLC or MPlayer, which most do).

As to what the problem is, my guess based on no info is that the version of Windows Media Player that ships with 98 is so outdated that it can't properly handle .wmv movies made with newer software. The file extension may have remained the same but the compression has changed. I have absolutely no idea whether or not the newest Windows Media Player will even install on Win98. I doubt it, but you could try.