Just a note from me that I had IE9 installed along with the new 64 bit flash square ActiveX and plugin. Both 10.1 stable flash ActiveX and plugin installed along side it.
When I uninstalled both 10.2 64 bit flash ActiveX and plugin and left the two 10.1 regular flash versions installed, I then uninstalled IE9 from Programs and Features-View Updates.
Using IE8 again, after a while noticed a posted Youtube video was showing it's frame, but was blacked out with no action. So I had to reinstall the regular 10.1 flash ActiveX on top of the existing install to get it to work again in IE8.
Also, after completely uninstalling IE9, MS conveniently leaves their IE9 feedback tool installed in Programs and Features. So uninstalled that as well.