I've been pulling my hair out lately over the fact that IE7 refuses to acknowledge that I already "have the latest Flash Player installed". Firefox 2 plays nice - but sites with Flash content in IE - nothing but blank content and annoying prompts to download a Flash player I already have.

Then I stumbled upon this patch from Adobe:
http://www.adobe.com/support/flashplayer/downloads.html

...and everything's been great ever since.

Hope this helps out.